What you're basically arguing, FL, is that you want the full-oval base for the player's Pokémon, rather than the semi-oval as shown in my concept. Whether or not Gen 5 Pokémon are to be added is a separate matter not related to the battle screen.
We may as well have the discussion in this thread, since it's about part of the GUI redesign. I'll start.
The battle screen will be fixed, and not float around and zoom in/out depending on what's happening. I have attached a screenshot taken from Pokémon White showing what it would look like without all the camera-moving. Looks quite familiar, doesn't it? The back sprites and player base in BW are all in the same proportions as they are in previous games (i.e. twice as big as depicted in the front sprites/the enemy base). The player's base is mostly hidden behind the message bar, so you couldn't see it all even if it was there.
The alternative, of course, is to make the back sprites and base the same size as the front sprites/enemy base, but I think that looks bad because of how it mucks up the perspective. Making the enemies half as big is silly for obvious reasons - they would be smaller than the sprites in Gen 1!
As a minor point, even less of the player's base and the backsprites are visible over the top of the message bar in BW than they are in previous games (this could be tweaked, but only slightly). And frankly, the BW base graphics look rubbish compared to the artwork from HGSS (both are supposed to be grass).
That's my main argument against full-oval bases - that you wouldn't see them anyway, and any other arrangement looks bad. If you have counter-arguments, feel free to share them.
