So far, the consensus seems to be in the compromise solution: keep the 3.x
branch targeting .NET 3.5 and 4.x targeting .NET 4.0.
That does imply a bit of additional work (backporting patches), but it keeps
things simple enough. A guideline for submitted patches should be
established, so the contributors do the work themselves when fixing bugs,
instead of deferring everything to the committers.
We could then establish a threshold of .NET 4.0 adoption that will result in
killing the 3.x branch, like 90% (I have no idea how to measure it, but I'm
wearing my free brainstorming hat at the moment. Maybe downloads/month)
Diego