I would like a mega-thread with suggestions on how to improve it. Can I help in making that possible?
+1 on changing Hiding to cost an action, I have trouble understanding why they choose to make it cost a bonus action, maybe to mitigate the absence of quarter/half cover?
I actually agree with this. Only the Rogue should have Bonus action Hide. By giving everyone Bonus Action Hide it reduces the power of the rogue.
+1 Entering turn based combat when someone attacks: when one of your teammates enter combat I don't think others should enter combat too, but you should enter turn-based mode as by 5e rules, every round is supposed to be 6 seconds in game time, so if not your kinda doing Max Payne's bullet time.
Also a big yes on this. However, only if the characters are on the same map or within a reasonable distance - if you are off doing your own thign and are not getting involved there is no reason to be put into turn based mode.
+1 Chequing things not triggering combat properly: There are a bunch, specially when doing range attacks, they feel more like bugs than design choices though.
+1? Involving sound: I don't think this one is that hard to implement, it might be tricky to properly show the player but could be cool, should be balanced with the range attackers because this will affect melee specially. The cool thing is that it might help specially with "invisibility", because now it's super strong.
Some creatures could have better or worse hearing also, as in owls in DnD among many other creatures:
Keen Hearing and Sight. The owl has advantage on Wisdom (Perception) checks that rely on hearing or sight.
Could also bring into play using Silence spell more, making the choice of changing armor for an encounter, seems fun.
With those changes stealth will still be really powerful, but will feel less as an exploit and there are many more probably.
Sound is already accounted for. If you are wearing armor that doesn't cause disadvantage on stealth checks then stealth assumes you are being quiet and your stealth check partially involves your success there.
I think the main change to make it more in line with 5e rules is to set the vision areas properly based on the capacities of the NPC/Monster. Vision is 360 in a combat situation but NOT in a non-combat situation. A guard could be distracted, staring ahead and not looking around, but once combat starts you are always looking around.
This is a harder change to make as you have to account for every single creatures actual vision capacity and range and then make it 360 degrees. Darkvision has to be accounted for and also Blindsight. This is a much larger project than it may seem.
However, the other two changes would make a huge difference in regards to Stealth not being abused by non-rogues.
