Sorry for the very late reply.
I originally based the barracks on reference from barracks on Acclamators in Legends comics (back when it was still canon). Generally the Empire isn't going to give their regular soldiers a lot of personal space.

And I guess this is more of a matter of personal taste, but personally I'm really not a fan of a load of empty rooms. The Empire will have pretty standardised barracks for everyone, so it makes sense to fill it in.

If there is a serious issue where maybe people can't spawn in properly or are getting stuck... Then that's certainly something I would look into fixing. But in terms of how spacious it is and the style of it, I think it feels appropriate as it is.