I would have perhaps preferred Phase 2. I like TNG, don't get me wrong, but Trek went to pieces after that (well, maybe after DS9). Likewise, I like TOS, and Phase II would have been TOS 2.0. The Uniforms would have been Original Series type, with additions based on the Original Series, the characters, the enemies, and so on.
I will note, it would have made a different Star Trek Universe. Canon is, after all, made up on the fly. Kitumba, for example, would have made for a very different Klingon Empire (and one in which "Klingons" were only the word for the warriors of their species).
I expect that once Phase II runs its course, there won't likely be more spin offs.
Well, many things from TNG were taken from Phase II. Decker became (with some rejiggering) riker's character concept. Ditto for Illia into Troi. "The Child" and "Devil's Due" were originally written as scripts for Phase II.
Wouldn't need rejiggering. From the start, Decker and Illia were supposed to have been the Riker and Troi. When the series was canceled, those character types were reused/used as intended for TNG.
I will note that Stephen Collin is 9 to 1 not going to play him. He joined The Motion Picture because he was interested in working with Robert Wise. That was it.