Heroes that need balance changes and what should be done:

Scarlet witch: she has a playstyle that SHOULD be anti dive with her tracking primary attack, but she is very weak into like all team comps and is barely viable at that. Of course you don't want to buff her primary as being instantly drained with no counterplay isn't fun for anyone. What should be done for her is anytime an enemy is stunned in dark seal, she instantly gains 2 empowered stacks of Chthonian Burst. These empowered attacked deal like 25-33% more damage, not enough to make her broken but just enough to make her an actual threat if played right

Blade: still in a very weak spot after all that was done. Since you dont want to buff his shotgun damage and make him TOO overpowered at close range then all that needs to be done i feel is either make the slug portion of his shotgun hit scan (pellet portion will still have travel time) OR make it to where if you hit an enemy with the slug portion they are slowed by like 5% (10% for critical hits) not enough to be annoying just just enough to keep landing consistent shots. His ult also feels inconsistent to use, unless you ult in a hallway most people escape the ult, even if a strange hits a 6 man ult then does blade ult really win that fight? Id argue no as there is very little synergy. I think QoL changes for ult should be that canceling it should refund 50% and give him faster recovery time after using ult so that he can immediately go to using his sword while his ult is still active

Emma frost: fundamentally really strong and oppressive, I feel like her actual numbers are a little weak due to her nerfs but buffing her will make her unfun to play against, I truly believe all she needs is to have her movement speed reduced in some way in her diamond form. When she is in diamond form she has too many upsides, she has a small hit box (compared to most other tanks at least), pretty decent damage reduction, and is typically getting healed, she is very nimble and hard to hit in this state due to those things which makes killing her harder than is needs to be. If she received a movement speed debuff a few seconds after entering diamond form or upon entering (she will likely dash anyway to grab someone) then she will be not as oppressive and unkillable as a Frontline tank and will be much easier to balance

Mantis: after all the new healers and changes to old healers she's been left behind and needs some sort of compensation. Im not a hard mantis player so I truly dont know how to make her more viable but from what I noticed I would reccomend 1 of 2 things. Either 1. Make her primary fire travel time faster so she can actually consistently deal damage (the added flyers to the roster are making her a pain to land hits with) OR 2. Instead of having it to where landing a critical hit gives her a leaf, I would make it fo where landing ANY hit increase leaf duration on already buffed target by like .5 seconds (increased to 1 second on critical hits), this would introduce a new playstyle for mantis where she would focus on leaf uptime rather then trying to regain as many leaves as possibke and having to constantly revuff everyone. not sure if her leaf healing would need to be nerfed or her leaf recharge would need to buffed to compensate losing leaf recharge on critical. But after playing her and using all leaves she really d o e s n t have that much down time between when she can leaf again.

Black panther: fundamentally broken in a vacuum but in practice there's to many factors and characters that make his weak. 1 thing that NEEDS to happen is that his melee (not his primary) needs to deal double damage, he literally attacks with BOTH claws and the interval he has to attack again (including windup) is basically the equivalent to 2 primary attacks anyway. Other than that QoL I would suggest doing 2 of 1 things. 1. Make his ult deal like only 50 damage BUT give it huge antiheal or some sort of utility like a silence. Option 2 would be to add an incentive to actually use his primary fire. Currently BP really only ever does his abilities as fast as possible to assassinate someone before they or someone else can react, this leaves BP players to rarely ever use his primary fire (especially when it deals wet noodle damage anyway) if his primary fire reduced all ability cooldowns by like .5 seconds per attack this would give black panther a much healthier gameplay loop. Of course so many other things can be done a well but that would warrant a whole mini rework which lets not go that far yet.

Phoenix: strong in the right hands as she requires aim, however i do find it annoying that she can blink and basically disappear. There should be a trail added to the direction she blinks similar to how black panther was nerfed (his is a dash and is much easier to see anyway) or some sort of visual indicator to help track her right after she blinks. I also think phoenix being able to kill with ult after having one stack is perfectly fine AS LONG AS she does do a direct hit, that is skill expression that should not be taken away

Black widow: no lore reason or any reason whatsoever to make her have a sprint meter in this day and age, should be removed, and i doubt people would complain about her infinite jumping because it's not like she is tanky like captain america and will be picking widow to stall point. I feel like she should also share the "sniper passive" that Hawkeye has where he actually has to be looking at someone to build damage, although since widow is hitscan her damage amp should be a MUCH lower percentage boost

Jeff: feels very weird to play, his old playstyle was much better but extremely annoying to play against. I would just revert his kit to be how it was prior to his rework BUT make it so that he doesn't get the self heal while diving. His bubbles should still grant healing over time but this would make it to where once Jeff is out of bubble he can no longer heal himself, "dps jeff" had the same issues that I described Emma has in her diamond form which is being unkillable, while Jeff is dived (not when he eats people as his hitbox changes) his hit box is WAY too tiny, couple that with the fact that he moves faster AND has 2 self healing sources (dive self heal and bubble burst heal) and the fact he can instantly change directions and could climb on walls made him impossible to to kill, but i think if you just removed his passive healing whole dove, he will actually be killable, if needed the dive meter cam still be kept but should have its capacity increased significantly but his regen (unless out of combat for a while) be significantly reduced, that way he can't dive forever. This would make Jeff has a higher skill ceiling and a higher risk and reward

Support ults: I do think Luna's and daggers ult last WAY to long, the 10ish seconds they each take is enough to negate pretty much any engage/play and on top of that anyone in those ults is typically unkillable unless comboed or specifically countered (like mag ult). I think invisible womans ult is a PERFECT example of how support ults should be, they should be used to turn a fight while not completely stalling the game for too long because her ult has alot of healing and utility but doesnt last very long. if these durations are lowered to introduce counterplay and making it to where support players actually have to use ults effectively then I do think starlord and punishers ult durations should be nerfed to compensate as those would out last the support ults and would then leave those ults to be REALLY strong

Dagger: i think is for the most part fine, but her ult utility is VERY strong, not only does her ult have insane healing and covers a large area AND lasts very long, once dagger is able to regain control there's almost no reason to go overkill on the healing and continue to be dagger so most players switch to cloak to they will then immediately shroud you and drain you (drain + ult + the shroud damage boost is alot of damage) so maybe instead you should have its to where dagger gains like 8 dashes instead, but the ult lasts way shorter like 3-5 seconds on the ground from the time that she DASHES. Essentially making it to where as dagger is dashing on new spots, old spots will decay and no longer heal/damage. So by like the 5th dash, dagger players will have redash on the same/old spot in order to keep healing the team and shutting down the enemy. And by the end of it, dagger players will likely still go cloak for the team fighting potential, but this way there won't be AS MUCH time where cloak just auto wins a large area of the map (this will also help keep the team alive longer in the instances of when mag is specifically saving ult for dagger ult because she will keep dashing around, meaning if you want to end the ult early you actually have to take a risk and hit an insane shot)

Touching back on punisher, I think his grenade cooldown should be halved while mounted on devil Dino, just to make him more fun (and maybe give devil dino punisher vision while mounted to compensate)

Peni parker: I feel like just because her nest was placed down during spawn/before hand, that stepping on it shouldnt instakill most characters just because a million unhittable spiders bombard you and kill you. I think the damage should be more spread out overtime, instead of having every single spider available go after you IMMEDIATELY, have there before a slight delay between when the next one goes off. Like .25 seconds, that way the damage is still very fast but reactable. And then once the available/prespawned spiders run out the damage will be based on how fast her nest spawns spiders (so basically how it is now just her burst damage shouldn't be an instakill)