The intent was always to keep Fuel agnostic from Theano and Blocks, though some stuff ended up leaking in via the floatX setting (Dima B. seems to have fixed this now).
I haven't been involved in development for about 18 months (no longer a grad student and a bit of a premium on free time, etc.), and it looks like development has halted for about 6. So I don't think Theano's end of life will pose an issue, but grad students wanting to graduate and getting jobs might, unless new people step up to the plate.