I guess I just don't understand why you need the tmux command key at all. If you pretended it didn't exist, what feature would you be losing out on that mosh has?
And when you're setting up a server it's easy to turn off the tmux status bar.
indeed. the only thing i need to do is copy a config file to set up the command key. the main use of the command key is to switch terminals and to access scrollback. beyond that, the key is rarely needed. working in any terminal is the same no matter how deep the nesting. i don't notice it.
the multiple toolbars don't bother me either. they can serve as a visual aid to recognize where i am. each terminal looks different. but in reality i don't pay much attention to them.
And when you're setting up a server it's easy to turn off the tmux status bar.