I enjoy Loki, but he's not a good villain, except for that tiny bit in Avengers where he makes them all bow. That was quality eviling. But it's like he's playing a role to incite the good guys because his actual plan to power always sucks.
See, that's kind of what I like about him. In Ragnarok, we see that Loki doesn't really have any idea what to do if he wins, other than lounge about and have people tell him how awesome he is. He's a rebel without a cause, and that gets underlined beautifully later on, when Thor sees through the incoming backstab, neatly reverses it, and makes the point that he's had 3+ movies of character development, while Loki is still stuck in adolescent rebellion.