To be honest, I never got to play Interceptor or Enforcer. I just heard they were bad, so I can't really comment on how good/bad they were. But I get the feeling that people tend to complain a bit because they were less "XCOM"-y, but then what do they want, if they complain about TFTD being a reskinned UFO:EU?
Apocalypse was great, but on the verge of being too complicated in it's politics etc. One of the other things that bugged me was you can't change the movement/animation speeds, so even in turn base, you had to wait for your units to run/walk the whole distance
In that respect, I think the "new" XCOM game was an interesting blend to make it more actiony and less management, whilst still trying to preserve a bit of both.
And as I said, I am totally behind people that try and make more out of their IP than rehashing the same game every two weeks.
Take XCOM: Declassified (or whatever it's called), it's another attempt to make an FPS. Will it be a good game? I've still not seen anything to do with it yet so who knows, but I like the fact that they're trying.
It could be interesting to see an XCOM themed RTS, sort of Starcraft/C&C style gameplay. You pick human or alien.
Hmmm, I'm almost tempted to try and make it as a Starcraft 2 Arcade map
Could have Scout UFO's as a unit, that allow picking up and dropping a single alien.