This thread reminds me of several blind wise men describing an elephant. It seems that most people here, including me, never studied there or know many who did. so, discussion is based on news items or on rumors what gedolim said/thought about it. Maybe, someone can find an actual YU-er and interview him/her?
I can easily see, and some people here mention this also, that the answer may depend on who we are talking about. Maybe R Kotler’s students do not need YU, some others might need Landers. But possibly those who go to modern day schools and public schools are already trained enough to survive that. I know of one family where kids went to a modern school and when they planned to go to YU, their classmates looked down at them as they all were going to Ivies.