I too agree that the game needs more units. Units are fun.
Unfortunately, they're very hard to create, seeing as you have to make a model and rig animations. It take time and specialized skills. Not to mention that we don't have actual modding tools yet.
Units were pretty hard to make in Civ V and unit making never took off like it did in Civ III or Civ IV. It sounds like Ed and co intended to give up better mods tools this time; they acknowledged that new art assets were hard to get into Civ V. I guess we'll just have to see when the modding tools are released.