I feel like most of the choices available are meaningful and if played at the recommended difficulty level almost all are viable with average ability rolls on any character.
Meaningful gets pretty subjective, I tend to agree, but I've heard people with a much higher bar of what's meaningful. Like, just everyone being on the same proficiency progression would get their hackles up.

Viable is less so, but it's still relative to both the challenges and the other characters. 5e gets a bad rap for being 'too easy' - I think maybe that's more a matter of the community's DMs' reaction to encounter design guidelines being so poor, err on the side of caution? - but, even if it is excessively easy, leaving inferior classes 'viable' relative to surviving expected challenges, they can still be rendered moot ('overshadowed') by OP classes, they're contributions simply not mattering makes then non-viable in the context of a cooperative game.
There is a big difference between equal and viable.
There isn't, really, equal or even identical choices could still be viable, might be, trivially so - if identical choice is viable, surely they all are!
They'll have a tough time with the whole meaningful thing, tho.
Not really. It depends on level. It does reduce the relative value of the extra fighter feats if you play to very high level, but it does not reduce them at low level, especially before the fighter gets any feats.
If you're playing with class/level as the only way to get feats (no V'umans or CLs), then, at 6th, the fighter has 2 feats and everyone else 1. The value of double the feats as everyone else has, even if that 2nd feat is very much a second-best/second-choice, is pretty nearly, well, double (and, if it's a feat that synergizes with the first, watch out!).
But, say, everyone gets a feat at first, now, at 6th, everyone has those 2 synergistic feats, and the fighter's bonus feat is a 3rd-string choice, it's come down in relative value, significantly, at best a 50% bonus, probably less.
As you go to higher levels, the value of the bonus feat is getting that 3rd-string feat 2 levels before eveyone else at 8th, then a 4th choice 4 levels early.... that's lower and lower value, but it's a smaller and smaller relative difference with each feat that's added.
It's a function of the way 5e.2014 presents feats w/o level gating or trees. 5e.2024 promise to improve that a bit, which will add some nuance to the timing of the fighter's bonus feats (like if minimum level for feats is by Teir, 6th is early Tier 2, and that'll be nice, but if an awesome feat is min level 7,

), but it'll still be, like, getting a bonus feat when everyone has 2 or 3 is just not as high-value as getting a bonus feat when everyone else only has 1.