I'm sympathetic to complaints against it because it does encourage a very different organisation of space than IE games. In IE games you were working with spaces you can see, the environment, while that kind of space management is almost impossible in POE's engagement (and stealth / combat initiation). I do think POE system as it stands makes some interesting space management impossible, though I think "gangbang vs. tactical use of space" is an exaggeration, since POE has its own space management.
I do think some of the grumbling is overrated. I've disengaged from people when I've needed to on Hard and it hasn't been suicidal. It is sometimes suicidal, which is the point. If I built a character with talents for disengaging etc. I expect it will be even easier. Enemies too move out of your engagement sometimes, and not to their death. After all, in that particular aspect, it is similar to NWN2 / 3rd edition and its attacks of opportunity, which were a factor but never suicidal.
hiver, I haven't read what you've suggested about engagement elsewhere so you may have covered it, but you mean giving it to literally only the fighter class? I mean, if we were to give it to all melee oriented classes it wouldn't make much of a difference in how the game plays, and if really only the fighter had it it would make them pretty powerful, no? Similarly, would bandits, zombies, and other "melee basher" creatures be expected to have engagement, in which case again, it wouldn't work so much different from how it is now? Because in most cases, players choose to utilise engagement with their front-line characters, and enemies as well. If you have a weak mage 'engaging' you it's not that big a deal to disengage.