This doesn't look like it's going to require a large time commitment to have fun with.
Plus, even if level creation isn't appealing these days, I'm confident that a full Nintendo produced 2D Mario platformer will be here (Surely, they're not just going to sell us a level editor and nothing else), not to mention user created downloads.
I've heard good things about Adventure Time twice in as many days now, but have never heard of Code of Princess or FF Theaterhythm [Edit: Latter two definitely aren't my style]. I also already own two of these since I'm a fan of Ace Combat and Ridge Racer.
But several of those are easily dismissed where I'm concerned. I don't like the direction that they took Castlevania in with the Lords of Shadow spinoffs, I have both PSP releases for Pinball Hall of Fame (Not to mention numerous console versions and Pinball Arcade), I have Bit Trip Saga for the Wii and haven't yet played it, I hated Asphalt Urban GT on the DS (Shovelware if there ever was one), Samurai Warriors isn't my cup of tea, Resident Evil: Revelations is on the Wii U, and Mercenaries was received fairly poorly.
But I'm not out to argue. The 3DS definitely has a fair number of nice third party releases and I definitely need to investigate several of them. I just think that it's much reduced from the heyday of Nintendo's dominance in this area, a line of thinking that you seem to largely be in agreement with.