There's problems, and then there are problems. You really need to consider what levels you'll be playing at, and what the "sweet spot" for the campaign will be. Everyone (myself especially) wants to make a game and be like "this train is never stopping!", but it's not realistic.
Even if everyone can reliably meet for months at a time, fatigue can set in, and the "new game smell" can wear off. New materials can appear that seem really fun, but hey, your characters are established, and this really doesn't fit the campaign...
Ahem. I digress. To give some examples of what I mean, if you want a low fantasy game where magic exists, but it's usually a problem for the players, and rarely an advantage, somebody playing a Wizard is going to be a problem, and Great Weapon Master is going to turn the Fighter from John McLane to John Wick.
If the game starts at mid-levels, has artificers cranking out "functional magic" to the masses, and the action is more political- well, sadly, the Wizard is STILL going to be a problem (lol), but GWM isn't going to stand out as much. Battles will be rarer, enemies will be better prepared (and will strike when you are least expecting it), and everyone is going to have more hit points. Nobody is fighting fair, and neither should you!
In a high level game where all the stops are pulled, the Fighter is likely going to be the problem. Not that he can't contribute, but more focus is going to be put on his weaknesses, and he's not going to have the narrative power over the game other classes might. The Wizard fits right in "yes, I think I can teleport us to the moon, and make sure we can survive.." and you'll be glad to have him around. Even if he is a cheating [REDACTED]!
As far as limiting options goes, I get that some worlds aren't ready for funny animal people or manga heroes. But let's look at Greyhawk. High magic, psionics, evil monks, crashed alien spaceships...this is a setting where just about anything could be found, just off the map. And that was what made it great. What's that, an insane demigod who built a dungeon with a Lewis Carroll theme? Dibs on the Vorpal Sword!
A serious game is a lot of fun, but cutting loose can be fun too. Don't be worried about how the players are going to warp your setting- nothing can stop that. Instead, stay open to how the game is improved by their wacky ideas. So what if some guy's Wizard has a 23 AC- the world is vast and grand, and there's more to it than being able to dodge shrapnel like some fantasy Rambo.