Merge is an excellent idea when two projects, frameworks, etc have the same goals (Not necessarily the same features). For example The Pylons Project taking BFG as is base and making Pyramid, with all the experience from Pylons community and BFG. This will make changes on both sides of the community but brings a new Framework with the possibility of improvement. I guess the idea is take the best from both frameworks y make a new one, better, with a big community, and a lot of knowledge from the previous experiences.