The problem with DMC2 is that it came out after DMC1. Although a fun game, with some interesting elements added in (circle being the proto-trickster style, ability to change weapons, etc.), it was an overall downgrade from DMC1. A sequel should be a lot better than its predecessor, like DMC3 was to the earlier games. This is why DMC3 is generally praised as the best in the series, and DMC4 gets mixed feelings from fans; DMC4 was definitely a good game, and REALLY polished up Dante's mechanics, but forcing Nero on us and sacrificing Dante time, backtracking, lack of bosses, gopping story, etc. let it down as a whole.
If we judge the games solely on gameplay mechanics, then IMO it would look like this: 4-3-2-1 as each sequel brought something new to the table. If however we judge the games as an overall package including mechanics, fun of combat, story, arsenal, replay value, importance of skill based playing, etc. it would, IMO, look more like: 3-4-1-2.
tl;dr - 2 is a great game, but it's overshadowed by the fact that its predecessor was a vastly better game