I got tired of the immense lag and wanted to switch back to using default Minecraft worldgen. Imagine my surprise when the game wound up hanging while trying to make a new world with a console error referencing OTG, which I'd removed. I've now put it back in and am just going to use a "default" setup, but the higher memory overhead is the entire reason I tried to switch back. Did I miss a coremod or something?

Hey Carnaxus, it should be possible to use worlds created with OTG without OTG installed. What's the console error when you try to load a world without OTG?

Make sure you have removed OTG-Core.jar from your mods folder (its a core mod that OTG unpacks when it runs for the first time).