Yes, it has bees suggested before, and they are aware that its a problem, I believe that Red said it was being worked on, or will be worked on in the future. Below is a link for players that have finished the E4, read through them if you haven't. I like your suggestion about the backgrounds though, that would be nice, I would also like to see boxes for specific types.
https://pokemonrevolution.net/forum/viewtopic.php?f=18&t=3814
This might be asking for too much, but it would be great if you could look at the Pokemon and their stats you have in storage via the pokedex, this way when you're out hunting a Pokemon with a specific natures/IVs you don't have to stop every 20/50/100 catches to go see the nature/IVs of said Pokemon.
Dynroth