I felt that ME2 did feel like a completely different game when you played paragon vs when you played renegade. The personalities were so different. You likely will get funneled but that doesn't mean they can't add a bit of diversity to the morality system.
Actually that kind of drives home what pissed me off the most about those decisions.
Basically all of them were trivialized in ME3. It was the middle game where your choices may have felt like they had weight, but they really didn't.
My first playthrough is a hardass infiltrator male shep sort of modeled after a roman imperator. I was fully willing to work with cerberus in ME2 because it justified the ends. In ME3 I found out that my choices were locked away and basically made to be pointless I lost interest in the game's "choices". (Which upon reflection paved the way for my ditching SP playthroughs and maxing my manifest in MP now I think about it.)
My Shepard would never have gone back to earth and relinquished the Normandy. If anything I would've taken control of Cerberus myself, which is what I was hoping for in the renegade side of things. I was always going to be a better TIM than TIM. Their resources, would become my resources.
Instead those choices all of a sudden made you look like a complete tool for working within Cerberus.
ME2 was the best of the series, but for those choices to have relevance beyond the feeling they give, they had to have impact. And ultimately, beyond seeing a reaper and a line or two about the collector station, they didn't.
No matter how "renegade" you get in ME:A, I doubt you'll really see any difference where it matters. And that's simply due to like I said, they can't make three separate games.
I'd love to see it done, but I don't think it ever will.