Be careful what you wish for..! One of the problems with arranger modules is, unless specifically designed to be a module, a lot of front panel commands (buttons) don't have MIDI codes. If you convert the keyboard arranger into a module, your main keyboard may not be able to select (from its buttons) things like Bass Inversion, ritardando/accelerando etc..

This leaves you reaching for the module to hit those, and particularly if you are using another arranger to control the module, it's tough to get the module close enough to reach those buttons without obscuring your main arranger's buttons...

We often take for granted how easy it is to hit important buttons and get back to playing with minimal disruption, but put them a lot further away and it gets trickier...