I'd say Mass Effect 1.

As a massive fan of the mass effect series and played the first one the most.

He said good rpg. Anything "RPG" related to mass effect 1 was beyond trash and if it weren't for every other element being beyond excellent, we wouldn't have had a trilogy. Theirs a reason the vaaaaaaaassssst majority of people consider mass effect 2 the best of the 3. The removal of the nonsensical RNG combat system (Hello, you're a super trained vet soldier who couldn't hit the side of the barn from the inside. I'd understand if this was the first game to try this and just failed. But for fuck sakes, its the one thing Deus Ex got shit for. Well, that and swimming.)

And the skill system works. Is it deep? No. But its better then pretending to be deep yet offering no real diverse differences between classes and playthroughs. Seriously, I've done all classes multiple times (Renegade/Paragon) so I know exactly how that tree works. Some moves are beyond broken, some moves are beyond useless. Theirs no in-between so you're always forced to pick the same skills over, and over, and over again. The alternative is using crappy, un-fun skills that just make the game harder and a lot more frustrating.

So, did mass effect 2 remove its RPG mechanics? Oh, theirs no doubt to that. But what we got instead was a really good 3rd person combat system with a lot more variety between classes. You still really can't do different builds per class, but I can tell you from experience that playing each class in mass effect 2 was a hell of a lot more fun and fulling then doing it in mass effect. It helps that they genuinely play differently as well and all have, at least, 1 powerful unique trait. Its pretty clear that mass effect become a better video game by moving away from being a near pure RPG.

Now, would it have been better if they went full RPG? Who can say, I know other devs have experimented but have always given up/abandoned the idea so it could just be shooters and RPG's just can't co-exist.

But don't look me in the eye and tell me that mass effect 1 was a "good" RPG. Its an amazing cinematic experience with amazing lore and amazing characters being dragged along by an archaic combat/leveling system which only succeeded in pulling you out of the experience and tend to go against the actual lore/physics of the universe to actually function as they do.