any list of best rpgs of all time that doesnt include diablo 2 is obviously invalid. i am pretty sure that in terms of man hours spent being played diablo 2 is up there with quake, unassailable on their thrones

as for mass effect, i loved ME1, but ME2 was a let down, it wasn't even an RPG, same as diablo 3 you can maybe call it an adventure game or an arcade game if your feeling generous but things like inventory management that 'put casual players off' is an absolutely fundamental part of it being an RPG

if there are no meaningful decisions in the game, its not an RPG

and if there is no user controllable character development it is an interactive movie, not an RPG