Well that's true. As far as I know, soldiers are listed by 1. rank, 2. number of missions and 3. number of kills. Given your experience, the base defense algorithm is a bit different, I guess. Like I said, I only switched tactics halfway my second game. I did have three MECs; 'Number Six', 'Clank' and 'Maya' -- 'Android' is an Assault nickname. The Temple Ship Assault went a lot better in the second game (3 Heavies, 2 Snipers, 1 Assault; actually the exact same soldiers as in the base defense) than in the first one (3 Heavies, 2 MEC Troopers, 1 Sniper).