Hello.
If I'm being honest, I haven't put much thought into porting it to MV since this post was made 3 years ago. I still have the same major issue, which is that plugin commands in MV are inferior from an end user perspective.
In order to make the two plugins as close as possible, I'd likely need to look into some kind of electron app that would take the inputs of a dev in a similar manner as the MZ plugin command window does, and outputs the results in one giant line for use in the plugin command event command for MV.
If I wanted to go the route of having the features be slightly different, the MV version could define the shops on initialization, so that creating them could make use of the plugin parameters in the plugin instead of plugin commands. But this would prevent Devs from defining them mid game, at the very least, and adding or removing or changing stock in a specific shop is still going to take a giant plugin command that'd be easy to butcher when you're typing it in, making it hard to use, and hard to troubleshoot if it's not working.
The best workaround I can think of is either breaking the plugin commands down into individual calls, and using regEx to parse them like note tags. But I'm not sure how that'd handle custom costs, and a whole host of other things, really.
Even as a dev who's not afraid of a little jank (trust me, look at the crafting plugin), myself, the prospect of having to type in a bunch of easily typo'd text instead of clicking from dropdowns and menus scares me a lot.
~Ramza