Never claimed you can't come up with in game solutions and we have tried the higher AC thing.
The fact you have to do that is the point. We like using feats those ones are a bit OP relative to the others.
You dont 'have to'. You can alter the feats if you want.
Those feats are not an issue for many gamers. I do get that they are an issue for others (including you).
Its just that Im sick to death of the same people making the same complaints (and starting a new thread about them) on a weekly basis. You, Captain Zapp and a few others seem obsessed with doing it. Its tiresome, and we get it.
That said, I and others are trying to help. There have been many proposed solutions given to you. Including:
1) Ban feats. They're
optional remember.
2) Rmove the -5/+10 and replace it with something else
3) Change your DMing style
4) Gritty realism resting
5) Change the numbers (-5/+1d10 or similar)
6) Only allow them to be used 1/ turn
7) Only allow each PC 1 feat.
8) Upgrade your monsters (increasing AC, proficiency, hit points, or both)
9) Use a mix of monsters
10) Tweak your encounter design
etc etc etc.
Another poster recommend stop catering to the powergamers and they get bored and try something else and it worked better.
That fits into 'Change your DMing style' recomendation above.
There isnt always a 'math based' answer to your problems mate. DMing is an art as much (more so) as it is a science.
If your players are always selecting the same feats/ classes/ options then consider the issue may not lie with just those feats/ classes/ options, but also
how you run your game.
Players being players will take the path of least resistance. They'll pick options that are better more often than not. So run your games differently, and you should see different options being picked.
For example if you start your encounters at long range (100' plus) in the open, expect sharpshooter to shine. If you only run 1-2 (deadly+) encounters per adventuring day expect nova builds to feature heavily (paladins, barbarians and full casters) and Champions and Warlocks to suck. And so forth.
I find that the guys that complain the loudest about 'encounters being weak' are the same crew that dont understand (or dont enforce) the longer adventuring day. They get an encounter crushed by novaing PCs, so they dial up encounter difficulty. This of course simply forces the players to Nova from then on. Instead of fixing the problem, this DM has just made it worse and all but rendered some classes obsolete (and rendered some 'builds' much better than others).
If you were to play in a campaign where the DM pushed a dozen encounters on you before you got the chance to long rest (but was permissive with short rests), it would be a very different campaign to one where you only ever got the one encounter per day. Classes would play very differently. Encounters would balance very differently.
Have a think about what you're doing as DM that enables problems at your table. Im not saying 'the way you play and run your games is wrong' but I am saying 'the way you play and run your games is almost certainly contributing to the problems you're having'.