I have no experience in c4d or maya back then as back then I was experimenting with milkshape.

Maya used a clever rose menu where you hold down a modifier key and right mouse button and you can navigate all but the more uncommon commands without moving any of your hands. A complex command requiring a hotkey or multiple menus ends up being a sub 1cm movement engrained in your muscle memory and maybe a modifier key.

And that movement is very easy to learn and memorize thanks to the design. I have to this day never seen an ui done better than maya.