Eh, DK could be confused with Diddy Kong by a newcomer to the series, I think referring them to "Donkey" and "Diddy" is fine. I actually hated seeing the abbreviation DK on Melee's selection screen... seemed too lazy and short. Spell out the name peoples!
As for Pokemon Trainer and Captain Falcon, I'm sure the NOA team has enough intelligence to use the more logical shorter versions "Trainer" and "Falcon" rather than "Pokemon" or "Captain". >_>
Regardless, I do find the whole name/image/icon combo a bit too distracting and large, hopefully it'll work better ingame than it does in the screenshots. Or maybe there will be an option to set it between this and "classic", so everyone could win!
On a side note, it seems that the Japanese version of Brawl still uses the English names down there. That's just weird.