I'd still buy and likely love the game if they discarded all RPG aspects and just gave us a shooter with a story and story choices, but that's not the direction I want the game to go, ideally. Either way the game will be good, but they would be very different games.

Personally, my FPS needs are better fulfilled elsewhere, so I'd rather my Mass Effect lean more towards the RPG side of things.

Really though, the two are not mutually exclusive. The "RPG" label has more to do with how your character progresses, what sort of choices you can make, how tactical/strategic battles can be, what sort of resources you have to manage, and how complex the gameplay is. "FPS", on the other hand, is defined by the method you interact with other objects in the environment.

There is zero overlap between these two things, and it is absolutely possible to make a successful merging of the two. It's just difficult. And in practical terms, achieving the RPG traits requires an increase in the game's complexity. And even if that's not technically against the concept of an FPS, it does generally alienate your typical FPS gamer.