This is a very important discussion we are continuously having and surely the most we can develop it here at the LAD, the better.
We really expect that MOD will stimulate the development of GPL LV2 plugins, both by amateur developers and professional developers who make a living out of it.
My personal opinion is that even if we build a "plugin store", there is no reason why he plugins in that store could not be GPL licensed. I mean, people can download it somewhere else, but they would have to compile it and manually install it in MOD, test if its ok, etc... while through MOD Cloud it would be one guaranteed click..
We also think its important to put the developer closer to the musicians, with open comments for plugins, developer profile and things like that, so the musician have a better perception about where the plugin he/she loves comes from.
Of course some developers wont feel comfortable with that and will prefer to close the code. We may have other players coming to the scene also, developers of proprietary plugins porting their software to LV2...
I think everything can coexist... and we can together think about mechanisms to give privilegies to FLOSS plugins, or , at least, to guarantee that MOD will be allways giving back to the FLOSS community....