While there may potentially be no "need" for Epic's engine specifically, I feel there's an urgent need for some decent middleware solutions on the platform. The variation in quality in the launch titles is simply absurd and don't think that's all down to budgets either, as even some wealthy and prestigous third parties are crapping out some absolute turds.
If Nintendo are as serious about third party development as they claim this should have been one of the first problems they tackled. Maybe they have, I don't know but the fact that they haven't even spoken to someone like Epic by now, merely to gauge interest is pretty damning in itself. Perhaps they really did send some of the first dev kits out to the Unity and Gamebryo teams as they should have done and perhaps they really are hard at work with Vicarious Visions to deliver some killer 3DS focused middleware but the general signs don't point to that. I hope I'm wrong and I'm sure decent middleware will eventually appear on the 3DS given time (as there's such a clear need for it) but thier shouldn't be a 1-2 year lead time here, this should have been one of their utmost priorites when initially contacting third party partners.