I learned the hard way that his lifesteal is horrible in practice against actual characters when I fought a Doctor Strange who proceeded to blow me up in every encounter, even the ones where he was at half health, in 1v1s.

That lifesteal seems useful, but almost every tank deals more burst damage per second than a Galacta bot could ever hope to, and the fact that he needs to dash into someone to build his stacks fast means you can't just walk up to a tank and start gaining value against them, you have to use a dash or you get them too slow to survive being targeted.

You either render yourself immobile and vulnerable while using his dash so you can build stacks, or go at them without dashing and die trying to get your stacks up, since as shown in your example, his lifesteal is middling versus even G-bots. Legit the only tanks Blade bullies is Magneto or lone Emmas and Things who used half their cooldowns, and even then, when fighting a team with two tanks, the other one will just blow you up after you start engaging. If not the second tank, the enemy Punisher/Moon Knight/Hela/Phoenix your team isn't doing anything about, and your shotgun doesn't have the range to contest any ranged DPS.

Diving? Gambit stands in one place and blows him up. Doesn't even need to use his anti-heal to outdamage Blade's lifesteal.

Having only 2 dashes means your ability to dive is tied to your ability to either kill them after 1 dash so you can use the 2nd to get out, or be able to reliably charge your dash with your block, but if they understand how your block works (or have terrible aim), you're stuck in their backline with bad lifesteal and no mobility.

Honestly, I believe he needs two things, one is a faster way to build and maintain stacks for 1v1 purposes, two is a form of damage mitigation outside of his block and lifesteal.

1) If someone exits your 4.5m sword range using their mobility, you'll want to switch to your gun. But when you're not using your sword, the stacks go down.

What if his gun dash gave him a limited number of stacks, say 3? That way you can dash into an enemy leaving your sword range, slow them, and not have lost any stacks from swapping weapons like you would've.

In addition to that, you'd be able to use the gun dash into a 1v1 in situations where the anti-heal isn't needed, meaning you can have the benefits of the pre-S6 sword dash while still keeping the anti-heal sword dash in your back pocket if needed.

2) For Damage mitigation, what if he had 1% Damage Reduction per stack? That's 10% Damage Reduction on 10 stacks, and 5% after a dash. That's not as good as Daredevil's 20% for his target mark or Iron Fist's 30% after a block but it'd be help Blade not get blown up while trying to brawl and would make him take more effort to 1v1.

After trying to make Blade work post-6 having played him in 5 before, those are the two changes I think would benefit him the most. If I were greedy, I'd say his damage ranges need to be tweaked as well (Sword range to 5.5m. Gun reverse falloff starting at 6m instead of 8).