I wager we'll get more models, but we'll get them slowly. It's really expensive to make/model a Harpy or a Ghoul or an Imp or an Intellect Devourer. It's just a very unfortunate constraint of MMOs, that they tend to release with less variety of models and mobs than we'd like.
I'll bet there are probably hundreds of 3-d modelers out in the fanbase that would love to create models for this game.
Imagine The Foundry for DM's and a Creature Modeler for them! I'm sure with a little communication they could leverage the fans into creating many, many D&D creatures for nothing more than some public acknowledgement somewhere.
I think if they did that this game would seriously raise the bar.