By the way, if you don't mind me asking, how has playing as Robin (and exclusively Robin) in tournaments worked out for you so far?
Well, for the most part.
First event we had was a round robin where I didn't drop a set. I credit that mostly to having an extra 2 weeks with the game, since I imported, but nobody else in my region did.
Second event was also round robin. I got second at that one, dropping a set only to our Diddy player. (I was lacking experience with the matchup at that point).
Third event was a ~30-man Double-elim bracket. Lost to Croi's Lucario in Winner's (he went on to get 1st), and to our Shaft (the Diddy) in Loser's to get 4th place.
4th was a house tournament at my place on an early Wii U copy Croi obtained through Nintendo of Canada. Got 2nd of 8, losing to Croi twice.
5th event (launch tournament) I got.... 4th again, I think. Lost to Croi in Winner's bracket (he won the tournament), then to Drake, who plays ROB/Rosalina (this was pre-nerf), in loser's bracket.
Overall, I haven't found a match-up yet that I think we can't win. I've beaten our Sheik/Mii Brawler player both times I've played him, though one was a ****-up on his part. Diddy I think is doable, but extremely difficult.
Losing to Croi frequently irks me, because the matches are always close and I know I can win, but Lucario is extremely frustrating to fight. He and I were frequently in Grand Finals in our Brawl metagame (playing Marth vs. Wario), so I doesn't surprise me that our rivalry has continued like it has.
That said, I'm confident Robin can be solo mained. Sheik and Diddy are the major roadblocks that you HAVE to learn, but once you've done that I think she's completely viable.
As it stands, I have made a commitment to myself to stay 100% Robin until at minimum the end of February before I consider exploring other characters for tournament play. I have no plans to break that commitment.