What are those ''limitations'' ?
Sorry this is going to be a wall of text. But you did ask...
For starters: Compatibility. Check out compat.cemu.info. It's not totally up to date but only 4% of tested games are considered "Perfect" that is to have no issues. Only another 16% is considered "playable" that is you can complete the game but there are issues(Graphical, bugs, audio, possibly occasional crashes.) That's it, 20% of the wii u library is playable on CEMU. The rest either doesn't work or has so many problems you can't complete it.
Next, Controllers: Only the Wii U pad, pro and classic controllers are emulated. No Wiimotes. Doesn't sound too bad but it does hinder some multiplayer.
Then there is the touch controls. You have to use your mouse and press tab on your keyboard to see the touch pad. This isn't too bad and is probably the best solution for emulation but I do find it to break up the flow of the game; especially in colorsplash for instance.
Speed: You do need a pretty decent pc for cemu to run full speed and some games just wont maintain full speed anyway. It was only recently with 1.7.2c that XCX really became playable inside new los angeles. Older releases would dip down to almost half fps at times. That does show that the emulator is getting faster though.
Graphics packs help tremendously but they don't give your machine more fps. They just stop the huge drops from new shaders being created. I never considered shader caching to be a limitation anyway. Maybe it's because I lived through the dolphin days. Also because once you've played a game for about 30 min to an hour the shader caching drops are significantly reduced. In my experience most of the "Complete" shader caches you can download aren't complete either. And there are some reports in the release thread that 1.7.3 is breaking compatibility with previous shader caches.
I'm probably forgetting some stuff I originally wanted to say but I need some breakfast. I guess bottom line is CEMU isn't a replacement for the wii u yet. When it's working well it's great but it's still a long way off from me forgoing the wii u for it.