Here is the thing, ME2 is a great game - but to me it does not feel like a sequel to ME1 in any way exept for the story - and that is why I think people were kinda disapointed.
I mean think about this - you play KOTOR right - then you hear a sequel is coming out - now imagine that the sequel is not the Sith Lords - which was like the original game but improved (imo anyways) - but instead it is The Force Unleashed - exept this version may have the ability for you to choose where you go and have party members....come on its an RPG right? Story - ability to choose your skill points - ability to change your outfit and your lightsaber.....
Come on now though - see that is why people are kinda upset - making a game that plays a certain way, and then COMPLETLEY changing it is going to upset people that really liked the first one - thats just how it is - now if ME2 was not ME2 but a first rendition of another game, or even ME1 then I do not think it would be that big of a deal.
Here is the thing for me - I loved ME1 because it was a really good mix of RPG and shooter - did it need its RPG elements improved? Yes. - Instead though they were pretty much removed. -
Why are people upset? Because the original game was a RPG with a little TPS mixed in - ME2 is a TPS, with a little bit of RPG mixed in.
IMO they should not have changed the game like they did - making a game and then making a sequel that is not like the original (gameplay wise) is stupid - You and I both would have been pissed if they made the second KOTOR an real time action game (think TFU) instead of being an RPG like the first - All these people who are like "get over it" need to try and step into the shoes of people that like the amount of RPG in the first one....then come to the second one and discover its nothing like the first.
Once I was able to let go of being bummed about what was missing and just take the game for what it was - I liked it - yet it does not feel like ME2 to me in any way exept for the story - I am not as immersed in the game - it is way more linear - I do not care as much about any of the characters - way less side quests - really it just feels like a really fun TPS with a good story - quite honestly I wish they would have just done away some other of the RPG elements at this point - I mean having to fuel up and buy probes...stupid...having to scan planets...stupid....none of these make my enjoyment or immersion greater - they just annoy me - I wonder at some point if someone thought " Wait we didnt add in something that everyone hates doing and is really tedous!" - Then someone says " I got it! Well make them use a scanner that is slow as hell to scan planets for resouces! And they will have to do it cause without it you cant get the best upgrades and abilitys!!! Ha Ha! "