I too think highly of Onegin. But it's tricky in performance, in my experience, because it has a few grand-opera trappings (mostly the two or three big group scenes, complete with formal dance numbers with big applause-grabbing endings) but is basically an intimate chamber drama, involving some rather subtle interactions and states of mind. If the dances come off too much as divertissement interludes for the audience, rather than part of the social life of these characters, it can throw off the scale of the piece.