You're exaggerating again. We did have quality alternatives against Bayern. They were already on the pitch. Marchisio, Dybala, Chiello were all out injured. Mandzu was first game back from injury, and basically not ready to play. We had 4 of our best players injured, and this depth you say we don't have, showed very well in outplaying Bayern for the last 30 minutes of the first game, and the first 60 minutes of the 2nd game.
That's depth. Calling it anything else is supremely retarded. We also had a bunch of our "depth" injured as well in Pereyra, Lemina, Asamoah, etc.
If Bayern had Lewandowski, Muller, Vidal out injured, we would have crushed them.
We also scored 5 goals in the 180 minutes, to Bayern's 4 goals. So in actuality, in terms of legit goals scored, we should have progressed.
Bayern won in the end, because Evra had a complete brainfart with 1 minute left. And we didn't have depth for our depth. It's not our depth that was the problem, something went badly wrong with our physical preparation this year, and we had far too many injuries. Either that or we were massively unlucky with regards to injuries. But neither of these things are "depth" problems. And don't say these players are injury prone. The only player on this team that could be called injury prone throughout his career is Khedira. Asamoah was robust like a tank before the last 18 months, so was Pereyra before this season, so was Chiello before this season and the end of last.