I'm not sure if you're into the 9.7 or 12.9 pro, but, my 9.7 A9X w/iOS 10.3.1 gets a g.b.4 metal score of 14451 while my A10 iPhone 7+ gets only 12500.
As far as RAM goes, I just read where iPhone 7/7+ beat out new android devices with up to 4GB RAM. 2GB will be enough for quite a while, I think. But the 12.9 has 3GB anyway, which is likely for the doubled screen real estate.
I see no reason to wait unless you do not need it until Fall, in which case I would say go ahead and wait. I would be surprised, at this point, if we see a new iPad Pro before this Fall, considering they are working on the new form factor (any updates to current iPad Pro form factors would not happen before the new one is announced). This is just the way apple works.
With the recent changes, I don't think we will see any event before WWDC.