Yamaha is famous for not making improvements in function on their PSRs when they do firmware updates. They just fix bugs. So I wouldn't make any suggestion like new voices, styles, or capabilities.
It is a pain in the behind to make a minor change to a file like a registration while keeping the same name and location. I think there are five steps. I think that Yamaha should put an option of "overwrite" with a required OK/Cancel choice before the file is overwritten.
Not as important, I think that in the parameter lock feature, it would be good to put volume and reverb where you can select what volume and reverb you want locked (R1, R2, R3, L, style, mic). This way, if you are playing in a cave-like atmosphere, you can keep reverb levels low.