If that's the design premise, it's hard to imagine how your plugin will further the development of PVD.
Why? You could still use PVD in the way you've always used it and prune the data. And then use an MC plugin for import. The difference would be that more people would use PVD.
You probably don't agree with it, but I do have a very clear premise. My experience as an MC and PVD user tells me it is very unlikely there will ever be a satisfactory solution for getting video meta data that is "built-in" to MC. J River might implement something, but it is likely to be simplistic and limited. It may satisfy casual users who don't care for more. I see no point in catering to them, however—they don't care!
The rest of us don't want to be restricted to one source of data, and want to be able to combine that data in any way we choose. That can require careful management of configuration settings and workflow which would be very difficult to control via a plugin. Yes, I know I could still do this and just use the plugin to import the results. But then why have the capability of controlling PVD from the plugin at all—for the users who have "simple" configurations requiring little maintenance? If that's the case, they should have no trouble running PVD.
I'm not really ignoring the "casual user" of MC. I just believe if one wants any control over the collection of meta data for video, they are better off using PVD directly. By "better off," I mean in ease of use, efficiency, ability to solve problems, and maintaining data integrity. I'm very much interested in more people using PVD. It's my hope a plugin that makes importing data from PVD much more user friendly would provide the incentive many MC users need. Once they try PVD, I believe they will discover for themselves this is the case. Also, I think the plugin will gain acceptance more readily if users understand PVD is doing the job of collecting and maintaining the meta data, and the plugin is just a rock-solid, one-click (once configured) tool for importing the results.
But all this seems rather moot...
I think I'll just add COM server to my TODO list for 1.1. I am pretty sure that it is the most recent version I will be able to concentrate on such things like controlling PVD from another App. Please use a simpler approach until then.
Version 1.1 has to be at least a year away, so I hope you don't plan on waiting. I realize you probably want to do it your way, regardless of my opinion. But might the "simpler approach" be something like what I suggest, and still be something you can build on later? If so, you might consider a successful "phase 1" plugin might generate enough interest to make things happen faster.