So perhaps in Xenocide, you could have Engineer and Scientist NPCs wandering around, similiar to civilians at terror sites. If you don't protect them, you lose them and have to hire more after the battle. The numbers may have to be scaled - you wouldn't want 100 engineers wandering around the battlescape - but I think this would add an interesting element to base defense.
Edit: Whoops, just realized this is the wrong forum. Please move it to Base Defense.
Further edit: And now that I've found that forum, I see this has already been proposed. Sorry for repeating existing ideas.
Edited by Kloreep, 16 May 2004 - 04:27 PM.