I’d like the option to be able to set the midi clock/transport globally, instead of per project.
That’s the first suggestion that comes to mind, but I’m sure I’ll have more thoughts as I get deeper into learning the Mono.
It’s a really fun synth. Kudos to the designers 
Along those lines, I’d find it useful to have a setting in each pattern to set the tempo, with an option of none (zero, perhaps), which would then follow the last active tempo from the prior pattern. Ideally, tempo would follow a priority of pattern first, last tempo or project second, and global third, depending on what was stored or not. Except, of course, when receiving and following external clock, that would override internal tempos.
That would be an interesting way to implement it.
a decksaver or any other transport protection could be useful
and maybe also a notice in French (even if the English version is quite clear despite my level )
Sequencer jump mode (à la Volca): you could deactivate pattern trigs and the sequencer would just skip them - which would make the pattern shorter - to allow for easy/crazy rhythmic variations.