Since they pretty much were begging WWE to make them available (and how last year even they got some minitrons at the last minute) and right now they are in the "polishing and bugfixing" phase of the game (remarked by Cory and Marcus), I highly doubt they were able to center that much effort into it, unfortunately.
I'm thinking this is going to be another "We'll be looking forward to making this a reality next year or future years" thing.
But... since Mini, Curve, and Side trons all really add to the feel of something, especially when it comes to complimenting the arena lighting with a specific color (such as Triple H's neon green, or John Cena's blue), I guess that I won't totally be annoyed with having to pick other people's stuff (as long as it's picked separate from MAIN trons)
Of course it's always annoying to have to pick a red entrance for say, Mike Rocket and have it say "Evan Bourne", but I suppose it won't KILL me to have to do it.
They do make entrances look quite good. But since this was a thrown in addition, I'm not very hopeful that they were able to spend any time doing custom ones.
But at long as they added text or Paint Tool to Main Created Entrance Videos (because Created Trons are already an option since 2009 anyway), I at least expect that.