One thing that I would like, is to have the ability to export a project to multiple platforms from one project file. Something similar to the way Unity3D does it. Also, I don't know if this is something that doesn't need to be coded into the engine or programmed by the developer, but a way for there to be cross platform interaction. e.g. a multiplayer game with OSX and Windows users in one match, or IOS and Android in one match, etc.
also, as a 3D artist, I think that many people may like a similar layout to Maya. not exactly as it is set up, but just how the menu hierarchy is.
Any thoughts, crits, suggests?