I was wondering, do developers have to pay a license, if they create their content with GMax? I mean, to make plug ins for it that will import/export their formats. From reading the license I think this is the case, but I am not a lawyer, so if someone knows better please let me know.

It was long while ago when i checked, i have slept since then. I beleive the price was $25,000 per title. You might want to do search on these forums that goes back a few months. This has been discussed before.

If this is the case, then a far better alternative would be to just buy 3D Max (or Maya, for that matter).