So including VST plugins is very difficult. Then I wonder : what other aspects should be useful to the .mptm format ?
Jojo mentions tuning, that's a good one, but what else ? Expansion of codes ?
By the way, I don't consider plugins as part of a tracker file, but as part of the application.
I think the first problem comes from all kind of install procedures of the plugins, while at the end, it's just a .DLL file, added in the proper directory.
So maybe it's time for OMPT to come, as default, with an extra package of free or open source VST dll's.
In this way a receiver could be certain to play the file correctly with OMPT because the composer used one of these.
But other plugins are possible too.
Many topics here about, next to .wav, importing a .mp3 as sample (or .ogg, at my concern).
Well, maybe it's possible to write a plugin for that.