I would argue that the 3DS's fate is far from assured in the West at this stage. ie it's just too early to call.
I think it's fate is assured... it will do well enough, but it's not yet assured to be a 'success' in the West, I'd agree with that.
I was happy to see a new Brain Training announced. I was talking in a thread the other day about the first year of DS versus the first year of 3DS -- and in terms of large core and casual gaming franchises, the 3DS smokes the DS - two Resident Evil games, a Metal Gear Solid game, Tekken, StreetFighter, Mario Kart (before the 1 year mark), SM3DL (NSMB didn't come until ~18 months)....
Now that the CPP is out, what would definitely give it more of a cool factor here in the UK is a couple of FPS/TPS games from western third parties: a Call of Duty, a GoldenEye, brands like Tomb Raider, Assassins Creed, or Batman. I think Vita will get those, and it will help.
The next FIFA and PES games need to have fully fledged online modes, FIFA and PES have only been passable so far on 3DS -- football is a huge thing to get right in Europe. Nintendo's new NES World Cup style game looks cool, and the football management aspects made me wonder if maybe a FM2013 game could work on handhelds... it'd probably suck compared to the PC/Mac versions, and need a lot of memory to play with, but it might be more technically feasible now than it has been in the past.
What its also lacking at the moment are those bitesize handheld distractions that DS had like Wario Ware, Polarium, Meteos, Brain Training or Elite Beat Agents. Pushmo is a good start, as its probably better than most DS puzzlers - and there are a few other eShop games that are really nice too. I was interested to feel, while playing the Nintendogs demo yesterday, that Nintendogs might work better as a downloadable franchise. I think it'd be a good candidate for DLC as well.
I feel like the landscape might have changed for games like that: pet sims, people sims, puzzle games, small learning or exercise utilities... there are similar offerings available on phones, and people don't have to walk into a retail shop to get them. Nintendo have already said they're going to look into offering retail games through their digital distribution channels, I think games like that should be the first on there.