Hard cap for stats makes completely useless a lot of perks including specialization when PC reaches 17-20 level of specific stat. For example there’s no point to learn Brute taking -1 penalty on Charisma if you reach 20 Str anyway. Every single perk that gives you a +X to stat affected by hard cap makes no sense in late game.
It would be nice to see some kind of soft cap for stats limiting them by 20 but allowing to break that max value with perks such as Brute, Burgher, etc.