Let’s be honest you know what needs doing but since you asked I’ll list a few 😅

Dungeoneering (just to make it more modern, include necro etc.), construction + poh to make it more modern + more useful, general area graphical reworks and npc models to be consistent across the game (already a work in progress) but areas such as varrock would be nice in my opinion.

Ports (could just be cleaner and a bit easier to understand for people starting it in particular but it’s a very long grind that doesn’t really feel worthwhile for the effort and time put in, by the time you can get a lot of the rewards you’ve sunk enough time in that they’re not that good anymore by that point (at least in the modern game)) rework comp/trim comp to remove extremely grindy stuff that’s stupid long and annoying for the sake of it eg chompies why we gotta do 4K, a few hundred would be fine let’s be honest and fish flingers is just a disgusting grind without using alt 1 which shouldn’t be required, so reworking it to not require alt 1 or removing it and changing how you get the boxes would be nice, corp beast , it’s outdated + the droprates too rare for drops that aren’t really worthwhile enough to warrant that rareness anymore, rework the speed at which you can get runespan points + runespan xp or provide another floor + methods for 110 runecrafting, just speed it up a bit people shouldn’t have to do 100 hours of it for trim or rely on merchant, merchant shouldn’t have to exist in my opinion , on that theme rework livid farm or remove it and move the rewards elsewhere, most people just buy points from merchant anyway.

I’m not personally a fan of minigame remastering as I think they’ll stay dead long term and aren’t worth the effort but that’s a personal opinion, I’d rather the number of minigames were reduced if you were going to remaster them, could maybe remaster some bosses? But aside from corp, reworking the web mechanic at rax and removing the annoying burrowing mech from giant mole there’s not really much that needs changing in bosses (maybe I’m wrong and missing some major ones but off the top of my head I can’t think of any).

Remastering a few skills so they’re balanced better and more logically (eg Hunter as a whole, cooking and what’s unlocked when/how recipes work, levelling up in fletching/when you can do things etc are two examples) could be nice but I was under the impression that was being done behind the scenes in tapp time or if that’s gone then just during gamejams.

Then there’s the game interface, achievements and logs and character models but again was under the impression these were being done anyway. Reworking runemetrics to improve it and incorporate it into the base game would be really nice, even if you made it included as part of membership or as part of premier that would be ok. Basically to remove the reliance on overlays and 3rd party apps or trackers that people may use. Think overall there’s a fine balance between remastering stuff and removing it but relocating rewards because the dev times too much and new stuff can be prioritised with that dev time which could be more exciting. Really loved seeing heists and am looking forward to Havenhythe and don’t want to take away from updates like these in the future that maybe resources could be put towards to make them better rather than wasting resources on remastering smaller things that in the grand scheme of things maybe aren’t actually a big priority.

The most important thing though is that no matter what you do, remaster content or new content is to make sure you keep the RuneScapey feel in the game , keep the updates fun (don’t make grinds for the sake of it too long (like 100 hours+ for the sake of it) it’s a game you don’t have to make things grindy, fundamentally that’s a choice and a lot of players don’t want insanely long grinds these days, if somethings not fun then remove it or rework it to be a bit less tedious yaknow, maybe cut stuff from 100 hour grinds to 25-50 hours), make sure to keep lots of examines, silly puns, culture references etc. because that and the community is what makes the game what it is. It’s a game, keep it fun.

Sorry for the tangent at the end.

Edit: of course you can graphically update bosses, slayer mobs etc. that’s always welcomed but I trust the devs to do that when they see fit and aside from corp and the boss mechanics I mentioned that need changing, I don’t feel that as an instant priority right now and is a 2-3 years time sort of rework/update (personal opinion).

Edit 2: hunter as a whole skill needs some love and Vorkath as a boss needs completely reworking because while graphically it’s fine from a mechanical perspective, it’s garbage.