Gyro controls are even worse than analog stick controls because they have inferior precision and require a greater range of motion for simple tasks than a regular controller does. The only reason is complete immersion, which more often than not fails because you're not immersed in anything. I haven't played any VR but it might work there, however, I highly doubt it because from what I have heard, it just isn't there yet (for immersion). In addition to that, VR still has no significant advances in tactile response or stimuli, so you're only getting half of the immersion even in a best case scenario.
To be fair, I don't think it's reasonable to start "what if" scenario-ing games that don't currently have a mouse and keyboard setup and assuming they did. It would be, and is, an unfair advantage if someone uses a mouse/keyboard on a console game that doesn't have native support for it. I know there are console peripherals that effectively add these options, but it's not as accurate as an actual mouse because you're still limited to the actual hardware or software (things like polling rate, dpi, accelerate/decelerate) so it's like using a mouse to control the already slow analog stick and it just feels weird. This is at least part of the reason they separate player pools (besides the technology layer) so that console players only play other console players and PC players only play other PC players.
However, you can compare games that do have both versions. Overwatch is a perfect example of this, where the console and PC platforms both coexist. The console version is not bad, but it has to sacrifice a lot of stuff for playability. This is the reason things like auto assist exists in the console version, otherwise players would have a hard time hitting each other with any sort of precision. I think Diablo 3 is a good example of something that works well on the console, but DIablo 3 doesn't require that much precision, and also has to have console-specific stuff in order to work (dodge) because you lose precision and response time using a controller.
I can't tell you how long it takes people to adjust to new control schemes. Each person is probably different. I know I have a hard time. I also struggle a lot with actual keybinds on PC games because I'm left-handed where most games default ship with right-handed keybinds. That means I have to find left-handed equivalents and remap everything, and there's also a modifier-key issue where I don't have access to all the ones a right-handed person does, so it comes down to removing keybinds I don't think are important or can live without, or finding alternatives to them.
If you want to try learning PC controls I really don't think any specific game is better than any others other than maybe starting with a simple game at first and then moving on to more complex, advanced games. Simple games would be things like Overwatch (some characters have very simple control schemes, others have complex ones), original Quake, Quake II, Quake III Arena, Unreal Tournament, etc. The more advanced ones might take more time getting used to, and i tend not to play many of those (CoD-type games). As a happy medium, you might try a Deus Ex game, or a game in similar style (Bioshock, System Shock, etc.) where you can sort of go at your own pace and play the game in different kinds of ways (stealth, tech, guns blazing, etc.). That being said, STALKER is a stupid game and I hate it. I cannot stand any game that aims for realism and has annoying stuff like weight limits for inventory, stamina, eating requirements and all that bs.
If you want to really get into some crazy peripheral discussions and setups, look at the people who take Flight Simulator games seriously. They have thousands of dollars worth of equipment and it's probably one of the best examples you'll find on this kind of subject.