Well then there's the reason why SonicGDK's adoption rate is so low.
This isn't your fault (and probably doesn't matter much to you), but UDK feels like it has to be rhinofucked into doing almost anything besides being an FPS engine, and UnrealScript isn't helping. Kismet is "good enough" for some things, but once you try to do anything with any degree of real complexity, you have to get stuck into the UnrealScript. I'm sure you're more than willing to help people figure things out, but when what they need to figure out is how UnrealScript makes any kind of sense, people go "meh, fuck it. If all I'm gonna be able to do is make levels, I'll go mod Sonic Generations". And hardly anyone is even really doing that anymore.
I'm installing UDK right now to give this another go, in any case. If anything does click and I manage to understand what the hell is going on, maybe I'll port it to UE4 myself. Don't hold anyone hold your breath though. It's not like I'm known for anything around here anyway
EDIT: And to be clear, Unity's architecture is a lot easier to grasp. There's really no debate on that. This is especially true if you're going about creating an entire framework, where you can make things even easier to grasp. Unity wouldn't be so popular for prototyping and indies if it weren't so easy to get to grips with.
This post has been edited by Aerosol: 06 May 2015 - 03:15 AM