For me, that transition from AutoCAD to Rhino was quite a while ago (somewhere near the release of V2), so I might not be the best one to ask. I will say thought that I certainly remember some speed bumps my transition, the biggest for me that I recall was transitioning from middle mouse button press and drag for pan to right mouse button drag, that took me a while
I think though that the argument that Rhino isn’t AutoCAD does carry weight however. There is a large segment of people who either didn’t come from AutoCAD or have learned and have gotten used to ‘P’ for planar for whom this would be a confusing change, or who are still learning and ‘P’ might not logically correlate to selPrev (or selLast). In my case, I’m glad I found Planar because now I toggle it almost as much as OSnaps (it is now F4, right next to OSnaps at F3). It is just a preference of tool use frequency, and were they should be placed.
This doesn’t mean that transitioning people from one platform to another couldn’t be made easier. In your case, I imagine it would have been nice if it were more discoverable to you that you could change aliases and keyboard shortcuts to better mimic a program you already know. I wouldn’t at all be opposed to some sort of AutoCADPrefs.ini, which would just be an OptionsExport which mimics as many of AutoCAD’s default preferences as possible. As I have said before, I haven’t worked in AutoCAD in so long, I’m not sure I could do a good job of this though.
I sometimes wonder if it would help if in the help docs if there was a header for each topic with a link that read something like “Can’t find what you are looking for, or still confused? Ask the community at discouse.mcneel.com” so workarounds like this could be found in a more expedited manner.