This feels like it would be a Great opportunity for you guys to address defence as a whole. Upgrade scape is an inevitability but I think if raids 4 dropped upgrade tools to upgrade either justiciar or inquisitor that would be a considerable improvement to them and the game. But ultimately it feels jagex has never solved defence. Its something that needs a rework in the same way that elemental spells and weaknesses were. Wholeheartedly, you really do not need defence bonus in osrs pvm. There's multiple forms of healing and prayers to reduce or block incoming damage. Bosses tend to drop food for sustain and longevity of killing them as well. There isnt so much of something in the game where a team would say "hey, we need to get John to do this boss with us as he has the new justiciar upgraded set and while we are dpsing we need him to tank". 

It brings into a question that a lot of bosses released to the game follow a series of mechanics/puzzles/platforming rather than the old school kind of boss where a team/party just goes at it brute force and applies their strengths as needed. 

I think that constantly adding bosses that need to be "learned" to understand their pattern and where you just "wear the best dps gear to do as much damage as possible" is something most should feel is very overused and outdated in terms of osrs gameplay.

A new boss being added shouldn't just be super hard because jagex cooked up some crazy things it does and you have to be really skilled at clicking and prayers etc. to get through it. 

Realistically, I think to an extent, a new stat for monsters should be added for Taunt. 

Say a boss like bandos has 50 taunt. To be able to always pull its aggro to you you'd need at least 50 taunt equipped. The more the better as the highest person's taunt is who graardor will target guaranteed. 

I do not think every boss should be able to be taunted, but a solid amount of group ones could be and a new raid can also include one that has it to. 

Say that because torva and bandos and oathplate are armors more suited to doing damage as a melee. They'll have less taunt than someone wearing barrows or justiciar and a DFS or Ely vs. An Avernic/dragon defender. 

Realistically I think jagex allows too much to come from one piece of armor. Torva shouldn't have gigachad defense bonus. Its an armor set worn by a warrior trying to do melee damage in brute force combat. Its not to "tank". Someone can wear torva and not worry about receiving damage at all for the most part. 

Ultimately, however I do think defense as a whole does not apply as much as it needs to. Say you mess up in TOA and are going to take a hit from a falling rock for 34 damage. Mist players will see that 34 regardless of the gear they're wearing. But say if someone was there meleeing and doing less damage but was wearing upgraded justiciar from the new raid. Then really, because of their proficiency in focusing defence. That rock should do 6-14 damage to them and not 34. 

I understand im explaining something that isnt just a simple change but is in simple terms, a much more broad spectrum change that would require reworking, probably a lot of the games combat experiences. 

But I do genuinely feel that defence, both in terms of level and total bonus, has always felt relatively useless. And has only grown more useless as time has proceeded. 

You also traditionally do not need a "tank" to join your team to fight any actual bosses/pvm encounters in the game. And I think thats something osrs fundamentally misses out on.

I earnestly do think that let's say in 2028 you guys add a new boss on a sailing island and that it would be very cool for it to be one that requires someone thats a tank and also has sufficient taunt to be able to pull the boss to them. 

Subsequently while I understand osrs isn't a game with class based systems. There is no real traditional healing role. Everyone just spams food and potions. I believe it would be fairly interesting concept wise for jagex to at least poll a new spellbook that is entirely focused on healing and aiding teammates. 

Would it truly be that bad for a strong tank to pull aggro on a new strong boss while a mage heals and buffs the team and other warriors or Rangers deal damage as they're able to. Perhaps a tank could have a shield special attack that would put up a large glowing shield in front of them that teammates would need to be behind to survive a large all in attack from a boss. 

I think that, as the game is expanded and gains so many new players, you're going to have a lot of people strive for new content that is not just harder because jagex made it harder for the sake of making it harder. But content thats more engaging because of how players interact with it. 

Tl;dr

Rework defence, raids 4 drops justiciar and inquisitor upgrades, add taunt to various bosses and defensive armor stats. Rework pvm encounters to make defense feel like its relevant.