The current strategy for android is to keep pushing the device level up through app developers rather than through carriers. I'm now at a point where I do all my devs targetting Ice Cream Sandwich and including the compatibility packages for older versions. This does not fix all of the fragmentation you're referring to yet, but it's a very definitive step forward. Of course, this essentially means that potentially all my apps are carrying the same patch of the OS with them...

Anyway about 80% of my previous fragmentation issues were solved with ICS. The remaining 20% though, are the truly hard ones!