Why? It's the future isn't it Oo?
Canon Trek already has the estabilished uniforms from the time period that Cryptic has set their game. And the uniforms Cryptic has shown us, are not it. Plus the rank insignia looks extremely oversized on the uniforms.
The game would be considered like the books and other "non-canon" materials though, they can add or make up whatever they want. Even Rick Sternbach in a recent podcast interview said they should go with what they feel and shouldn't be that burdened by the canon as it is a game, adding that it is always more interesting to see new things in the Star Trek universe. Now I don't agree with everything they have done, personally, but it is up to them how far they want to go in this direction.
EDIT: I should add that we also don't know the extent of the avatar customization yet either, I would feel that uniforms could be made available from TNG onwards if you wished.