I think it’s great that Ali is willing to go off on his own with a new version of GNOME that meets his needs and those of his collaborators. The beauty of free software is that one has the right to tinker in whatever direction one wants. One size cannot possibly fit all, so if Ali wants to make a different size, more power to him. Those who share his views now have a place to devote their energies.
I also must echo Mikael’s concerns, and say I will not miss his somewhat abrasive personal style in our midst. It will be interesting to see how his new collaborators negotiate that sometimes difficult terrain.