Games of choice and liking are subjective. I personally think ME1 is the best of the three. I am an RPG freak tbh, so ME1 really appealed to me. Changing the ability to use any weapon no matter the class took a bit of the RPG out of that game but the player agency choices still have huge impacts.
Having said that, if you consider the story of ME2, then the battles seem appropriate, considering the reapers are using the the Protheans they genetically modified to combat losing one of their own in ME1 (Sovereign), so this makes sense. Considering the reaper's goals of no quarter and lives saved, batytles are to be expected. There are RPG elements in that yiur choices determine if squadmates live or not and make it into ME3, which is far better at RPGing than ME2.
