Yeah I really feel like they would've gone with the original plan of the game if people hadn't have rushed valve so much
cause really the old storyline was much longer and consisted of a lot more places
Heres a pic of the old storyline:

also it seemed to contain a lot more combine tech places which I really wished there were more of
Being in the citadel was my favorite part of the games just cause of the cool feeling you get when you're in the place.