TFTD was a different game really. It had different balance and different concept of combat - in my opinion a step back from the first game really (and way more silly).
I'm not saying this to bash TFTD as a game, because it was still very enjoyable, but to explain that I don't feel restrained by what was going on there; I'm making mods for UFO: Enemy Unknown / X-Com: UFO Defense, and I'm balancing stuff against this particular game.