5E Rules, slower progression. Better or worse for NWN

I recently noticed a few things that 5E that I like, dislike and am not so sure about.

One thing I’m still on the fence about is the slower progression mostly the part that replaces BAB with proficiency bonus. It makes sense that an adventurer would naturally get better at adventuring as he leveled and this improvement would directly affect his ability to do everything he does. However, this means that a fighter isn’t any better at fighting than anyone else? Since BAB is now proficiency level wouldn’t the fighter’s attack bonus be the same as anyone else’s.