No, the CPU. GPU is close to no problem performance wise.

Seems kind of pointless when the game is in HD and 60FPS.

1080p ? Better anisotropic texture filtering ? 

Seems like alot of work and hassle for something that small. This isn't a PS1 game and the gap is getting pretty narrow. Next generation, what will be the point? It's just getting harder to justify this stuff imo outside of theft. 

Save states ? Higher quality anti-aliasing ? Higher resolution textures ? (It's possible to do that just so you know.) 60FPS patch for native 30FPS games ? 

Better framerates ?

Everybody is different but for me, it's not worth it. Current generation games aren't going to be improved enough to warrant myself going through hoops to play them that way. 

Well, others feel different and I am glad that the hackers decided to also think different.

I can understand that since the latest in emulation does require some fairly expensive hardware ... 

"Improved enough" is subjective and I do think most of us will get comfortable soon enough with the image quality in the next generation ...

It's been some time since i read through Dolphin docs and FAQ's but i remind that the way the GPU works can be a major problem with games, especially integer calculations from the GPU seemed to be a problem. That was some time ago though.

Oh, you mean accuracy and not performance. I think they did some good things with DX11 so that is now sort of a requirement and they dropped support for DX9.