The following discussion is posted not because I think user-designed units are a negotiable part of the game, because I have the strong impression that they are not. I'm simply posting because I loved Master of Magic, HoMM 2 & 3, Master of Orion and the Civilization games and have strong hopes and anticipation of Elemental.
It sounds like some of the features that I was hoping to see in Elemental are not planned for the game, and I wonder whether many of them are absent because they are incompatible with user-designed units.
1. Magical creatures - One of my favorite features of MoM. Are they rare and not part of player armies because it would be too complicated to implement them as user-designable units?
2. Complex unit stats - If units are predesigned, you can safely have more complex (stat-wise) units because players will learn the complexities of a given unit over time.
3. Understanding the battlefield at a glance - Predesigned units are instantly recognizable on the battlefield from their appearance, so you know the military situation at a glance, without mousing over every unit to read its infocard.
It was fun to design the ships in GalCiv because of the variety in ship appearance you could create. Without that benefit in Elemental, I beg the developers to consider whether the oppotunity cost of user-designed units is worth the things you have to give up? Thanks, I felt a burning need to get that off my chest.