Fairly sure Newfie is broadly used as a colloquial term of endearment in the rest of Canada, by Newfoundlanders and non-Newfoundlanders. There's just too many syllables
Having grown up with so much predominantly east coast originating comedy, and around so many Newfoundland diaspora, I guess it never occurred to me that there was any real negative connotation whatsoever, beyond poking a bit of fun at some of the presumably antiquated cultural stereotypical differences via self-deprecating jokes that most people from smaller places have their own versions of and don't take too seriously.