What is the ratio people are running?
I have 9 moogers and only 1 CP. I think it is time to get another.
Do you need it for anything? I would suggest letting that be the judge of if you need it or not. What have you wanted to do that you couldn’t do for lack of a CP-251? Ask that question or keep track of future patches you can’t make make because you don’t have one.
Unless you have G.A.S. then go for it 
6 foogers 2 CPs, here.
I like having two for mixing and using two independent lfos. The sample and hold is cool, as is the static low pass filter(?) on the S+H input 3 (I think). Anyway, I like them very much.
Now all i need is a 50 point patchbay and a shotlaod of cables. Then I can plug up all those holes Moog carelessly left in the back of all the Foogers.