I just finished the game for my first time on ironman normal. The ending was... horrific. If I had been on classic or impossible I would have lost. I came in with 2 psi snipers, a psi heavy, a psi support (one of my original squad), a normal support, and my Volunteer was one of my original assaults. Got through to the last room without a scratch, immediately was caught offguard while positioning, and was unable to position myself properly. 1 of my psi snipers, my psi heavy, and my normal support were all taken control of. Due to positioning, the sniper had a clear shot on all of my troops, the heavy was right next to my Volunteer, and the normal support was next to my psi support. I had my sniper shoot at the Uber Ethereal twice, and one connected for a crit which knocked it down to 2/5 of its original health, and my Volunteer mopped up the Mutons with a rift, while I had my psi support create a barrier that would (hopefully) stop hits on my soldiers by their comrades. This failed miserably. In the end, I ended up killing the Ethereal controlling my heavy, but the other sniper and my normal support were still controlled. Without any other option, I ended up suiciding my heavy to kill the sniper and the support due to extremely low health on my other units (they would not have lasted through a plasma shot). My assault and support had their shots reflected, almost killing them, and my sniper had his first shot reflected, dropping him to 1 health. I fired a second shot, knowing if this missed I would lose, and it critted the Uber Ethereal. Cue game over, with only 2 units returning home of the 6 sent, and only 1 original squad member in the entire game living to completion. Ouch.
Edit: In retrospect, shoulda brought mind shields.