One of the main reasons many get into any mod scene is the prospect of emulation. People relish being able to play the classics on as many different platforms as possible. That's where RetroArch comes in.
Consider RetroArch to be the One Ring. Instead of needing to scour the internet for different emulators that may or may not work, RetroArch comes equipped with the best, designed to run within its own engine: one emulator to rule them all.
Libretro, the group behind RetroArch, is currently in the process of optimizing its tech for the Vita, but has already seen great success. New builds go out regularly, and there are a host of emulators running at near full-speed, right now—all of which is being achieved without the same kernel-level access HENkaku has. If there's an emulator of a system designed before 2000, the Vita will have it.
N64 emulation is probably likely on Vita, but it's hard to say when. – Seong Gino, 'RetroArch' tester
The PSP, after years of people tinkering with its hardware, was able to achieve a feat many thought impossible: N64 emulation. It wasn't great, but the DaedalusX64 emulator was never about perfection—it was about doing something nobody else could. It's essentially a dick-wave from the people with an innate understanding of how the system works.
So once more developers have kernel access, could we see the Vita complete the work the PSP started?
"N64 emulation probably will be likely on Vita, but it's hard to say when," says RetroArch tester Seong Gino. "It is indeed amazing that the PSP was able to do some Nintendo 64 gaming, but that was after years of development time, a bunch of speedhacks, and the only game that came out perfectly fine was Super Mario 64. Anything else either had graphical inaccuracies galore, sound bugs, or just wouldn't work.
"Now on Vita, it goes back to the whole lack of driver support at the moment; without any way to utilize the GPU, we would be at the same place, just about, as the PSP and DaedalusX64. But in the future, if we are able to use the GPU effectively in homebrew, I can definitely see PS1 and N64 getting good enough performance on the Vita. Heck, I can imagine Sega Dreamcast—with a port of Reicast, perhaps—running on the Vita about as well as the Nvidia SHIELD Portable."