Hi Frank, you have strong arguments to stick to the GPL and one point's for sure:
- GPL must be a possible license choice for all current and future externals basing on flext
However, flext is more general and in the Max/MSP world open-source is not as widespread as in the PD universe. As a musician i'm often depending on stable, feature-rich performance tools and if they do the job i'm willing to pay for them. It's easy to develop large, complex packages with flext (see vasp) and i want to encourage that, be open-source or not.
So the target license should strongly encourage the open-source idea (and be compatible with the GPL), but allow commercial applications as well. That should be fairly easy.
best greetings, Thomas