All the things you mention are in fact supported in Final Cut X if you know where to look, so either you are not looking or are not familiar with the program. The masking tools are adequate for most tasks, you can create complex shapes with editable key points and curves, and more advanced masking work can be done in Motion - just like you would in Premiere / After Effects. Frame precise editing is easy with a key command. Roundtripping with Resolve and Logic (and many other external programs) works well though XML. There is support for external broadcast monitors as long as you have the correct hardware on your Mac and libraries can be stored on RAID arrays, even on a local network assuming your network is fast enough. Red R3D files works as though it was native via a plug in, and with a powerful enough Mac - specifically an iMac Pro, you can edit all the way up to 8K in real time.
The genius with Final Cut X, in my opinion, is the simplicity of the interface. Many advanced features are available with a keystroke or click of a menu and much of the interface is contextual - only functions relevant to the tool in use are shown on screen at any given time. The overall interface is clean and you can completely focus on your timeline and footage, any unneeded/unused features are neatly hidden away but easily accessible if needed.
Anything by Adobe, on the other hand, looks like a pile of menus puked all over the screen, by default you have dozens of open tool tabs, icons and menus all open with most unrelated to your current selected tools and tasks, and forget about easy multi-cam or compositing, you can easily have a seizure with your head spinning so much trying to keep track of what menus go to which viewer and what is selected where.
