Hi Stephan!
Yeah, CC0 is such a no-brainer to me to attach to anything provided for a free; I sorta don't understand why anyone would have anything more restrictive (I mean + usual no warranty for code - MIT or similar, but it's a technicality).
As for "don't redistribute or resell"... I don't see it as a harm directed at me, although it's a d***ish move towards the buyer, I guess. Would a license stop such a person though? Why and how would I even chase the guy. CC0 makes it so much easier to use. Alternative gives me nothing, doesn't prevent abuse, doesn't help the third parties in any way.
Just my thoughts : )
So yeah, more open-source please, and good luck with your procedural levels (it's a rabbit hole, I know, I've been there!)