This is not to take away from Jay Leno’s replacement Jimmy Fallon on The Tonight Show but rather to emphasize what a great opportunity for another network (and of course, I push for Fox broadcast.)
Jay Leno is #1. He has kept THE TONIGHT SHOW #1 for 20 straight years! How do you not want to hire success?
I don’t know what the programming is on Fox opposite The Tonight Show but I would try to move programming around and put Jay in his same time slot on Fox to compete with NBC. I don’t know who would win, but competing is fun and makes TV more of an adventure for those involved. In the article below (see link) Leno says he won’t do another late night show but I bet it is in his blood and with the right opportunity he would jump at it.
In many instances talent sign non compete contracts with the network they are leaving but that is in exchange for a sum of money. Leno has so much money that I can’t imagine that he would sign a clause that would imprison him.
Here is an interview with Jay Leno in LA Times