Neelix was more of a broken character than break out unfortunately. One of his more interesting moments early on was when he was aghast at Janeway's attitude towards exploration, and it's an attitude I'd wished he'd held onto. Instead we ended up with the boorish overprotective storyline with Kes and Paris, and of course his overly jovial personality was grating.
He was toned down somewhat in later years though, and throughout the show he had a few very good dramatic episodes, that seemed totally at odds with who he usually was the other 99% of the time. Such an odd character.