I would be very interested to see some data on that, say gathered over a year or two. Licenses decision really need more scientific approach, and if the main desire from choosing a license is to attract more third-party contributions, GPL vs LGPL is an interesting situation.
Have you seen a change in third-party contributions from companies for the libVLCcore after the license change? Its not the same type of software as the mods, but would still be interesting in this context.