As some one who learned in YU for many years and was in the kollel I would like to share my thoughts on what I perceive as the weakness of YU.
YU does not give a person an opportunity just to sit and learn after college or semicha. I graduated college and wanted to learn for a few years before going out to work. The only way to do that was to join the Semicha program which I did. Why did I need to that? I did not want or need semicha and I had to do things in the program which were a waste of time for me.
The same thing applies to someone who wants to learn after semicha. The only real option is the kollel elyon which is small and only for 3 years.
This leads us to another point, how much does someone really know when they get semicha from YU. Many of the people who get semicha really started learning in their year in Israel at 18. After 1 or 2 years they came back and went to YU (college) splitting their time bewteen learning and college. Then comes another 3 years of learning in semicha with many people splitting their time and getting a Master's degree in Revel or Azrieli. The 4th year of semicha is spent doing shimush. If we add it all up it doesn't amount to that much. They certainly don't know shas. The semicha itself from YU lists off the areas in Halacha that the person learned and is בקי in. It lists hilchos nidda, eruvin, geirus, etc. What really happened is that the person heard a few shiurim on hilchos eruvin, nidda , etc. and took a test, to call them a בקי is a joke. To be a בקי in hilchos eruvin you have to learn gemara eruvin in depth with the Rishonim and then to learn the ש"וע, a process that takes a tremendous amount of time which no one in the YU semicha program has the time to do.
Let us look at 2 friends of mine, one went to the kollel elyon and then became a Rebbe, and 1 went to the Mir in Yerushalayim and is still learning in kollel 10+ years later. Who do you think had the chance to grow and become a bigger talmid chacham? It is very nice to be a rebbe, but it takes away from your own learning. The friend who learns in kollel at the Mir is a בקי in shas and ש"וע from his years in the Mir. He is now much better prepared to start giving shiurim. He is now starting to give shiurim and you can see his bekius in every shiur that he gives. The extra 10 years learning allowed him to grow tremendously in Torah and fulfill his potential while at YU you are forced to stop learning full time at a much earlier age.
I think that YU goes to 1 extreme and the RW yeshiva world goes to the other. YU doesn't allow anyone to sit and learn in kollel for 10 years even though for top guys this is the way to produce Gedolim. The RW yeshivas on the other hand want everyone to just sit in kollel for 10 years even if they aren't progressing and/or are not cut out for it. It is too bad that we can't find a happy medium.
I do not mean to bash YU here. I am a product of YU have many friends who are Rebbeim and have the greatest respect for the Roshei Yeshiva. I am just tyring to point out what I see as a weakness in the YU system.