I think 5th is right to make feats optional. One of the strengths of 5th is you can play the flavor you like -- you like 3.5 best? Use feats. You like 2nd ed best, DM can say "no feats". 3.5 was fine I guess, 3.75 is better but both are in meh category.
Now you are spot on with the Warlock comments. Warlocks are a 4th edition class and suffer from all the 4th ed problems. The answer is always. always "teleport and eldritch blast". Good if you are a doing tournament play with disposable characters but otherwise boring. So I just keep saying "I hex goblin #2 and use my eldritch blast" all afternoon? I'll add that the easy healing in 5th is completely immersion breaking. Nothing a good sleep can't cure! But both point to the same issue -- if the warlock wasn't included this would have alienated 4th edition fans and they would have made lots of noise. Both of them!
On battlemasters If you are going for a low or medium magic setting you need something to make fighters interesting. IMO 2nd ed did this best with intelligent weapons and the like. In the late game a fighter has a number of items that gives her multiple options in combat. In a medium magic setting like 5th ed fighters need to do something other than say "I slash with my sword" all day.
TL;DR 5th is a compromise system one that allows people to play 2nd, 3rd or 4th as they like. The devs should trust it more.
