CorvusFerreum said:
Since it wasn't mentioned yet (I think) I go ahead and say:
Dawn of War (went from squad based RTS with conquer mechanic to squad tactics game)
The second installment was really different from the first one, especially in the campaign, and many were disappointed by that. I personally likes the approach to take the series in a new directions and had a blast with all installments. I really hope that they try something new when (DON'T FUCK THIS UP SONY! I DARE YOU!) DoW 3 comes around. Reinventing the formula everytime and delivering a fresh experience in every installment is a nice and unique approach to keep franchises breathing, at least I see it that way.
But it is not deniable, that they strayed far from their roots (although I wouldn't really say they have lost their way. Perhaps it even is their way to change once in a while)
The multiplayer was great in both dow 1 and dow 2 IMO. Dow 2 played far more like (almost exactly) CoH which definataly isn't a bad thing.
But the single player campaign in dow 2 was a real let down. It just became a level up your squad simulator. No real tactics/strategy apart from "stick your guys in cover".
So, IMO, they definately lost their way in the campaign, if nothing else.