My first post, woo! Personally I think this theme could work if you created some models specifically for it.
Pearly Gates, Moving Cloud Platforms, etc. I think you had the right idea with heaven floating. The difficulty is coming up with a general idea of what "heaven" is and then combining that with actual fun gameplay/level design. I think arena or koth would work well for this type as they are relatively small compared to the other game types.
The last picture looks just like another TF2 level taking place in the same environment as so many other maps. It's too bad you scrapped the floating theme because I think that's where your map really set it self apart from all the other ones. However, I know it's difficult to get/make decent looking custom textures and props and the whole mapping process isn't exactly easy either.
With what you have though, I see a lot of potential. Keep it up.