It's the difference between having only one option, and having a number of options, one of which is always the best: no difference, at all, really.
Since any given at-will option is always available to compete with every other at-will option, they're most susceptible.
(I'm pretty sure I'm just agreeing with you, there.)
Those builds were usually strikers, which, IMB, make's 'em boring, anyway, from the start. Power Attack at least could be a bit situational. And, yeah, trip builds were cheesy and illustrate the issue perfectly - it makes no sense that tripping is always the best thing for you to do vs anything you can trip, at all - but, damn, with Reach & WWA, they were more fun than Fighters could legally have had before, nor even, mostly, since. And the Champion Fighter (a prime consumer of feats, afterall), and the few other non-spell-casting sub-classes, of course. In a way, it doesn't acknowledge it, at all - 5e's 6-8 encounter/day is a way of sweeping the issue under the Rug (of Smothering). Nope, your DPR's'll average out about the same over the day, it's fine. Everything's fine. We're all fine... here.... thanks - how are you?The 13A fighter manages a similar result, though, by randomly determining the maneuver for you.