A few things - it's going to be political of course (gaf is a bit of a political place for starters). Activision hasn't done much positive with the brand in some years now, and the dev of this game is typically finger-pointed as the culprit responsible for those lows in recent years. It's not as if people didn't have good reason to worry. On top of it, there was a tinge of cynicism here and there but overall expectation was pretty decent for this game.
As for the engine, not fair to blame it, on the one hand I am sort of surprised that they didn't use the existing THPS engine (then again, it's probably mothballed a fair bit now after some years of inactivity). Not sure why they went for UE3, probably had their reasons (speed and ease of implementation, potentially way less cost than dusting off/rejiggering older engines, or even building a new one which would really be out of the question for what's essentially a budget title). Ultimately a game like this is probably more intended to court a more casual market in some ways, and in that regard many of the decisions probably made a lot of sense - in the short-term, at least.
Anyway I've still yet to launch the demo so I won't praise or damn it at this point.