So many morpheus UP is not really a problem in the program, there are that many because morpheus holds the largest user base. The problem is that some of their childs don't share that many files, maybe because they are on slow connections.
But the problem is not the Ultrapeers, I saw that each one of those has at least 200 childs. You can see this by browsing the network (a gnucleus feature), if you want to see it, just open your browser and type http://{morpheus client ip}:6346, you will see that most of them have lots of childs, and are well connected to other ultrapeers.