I don't see why there couldnt be a spring Gens Classic, I know Blitz, is about to begin draft, and GDL is just starting to play, but starting a spring classic in late March, early April start date should be fine, GDL should only have some playoff teams left, and Blitz will be on going, but for Classic B I know there is about 6 coaches not even in Blitz, and probably 10 more that will have games completed, and may, or may not have playoff series to play. Most Classic A guys are always around, and should be able to fill enough spots for both an A, and a B IMO.
I am new here so maybe I am wrong, but I am just going off of the new crop off players that have joined, and how active they have been, and like I said some of them are not even in Blitz, or GDL as both waiting lists are at least 5 deep if not more.