Would it ever foresee a possible future compatibility update to be made between SpongeForge and OTG? This is what SpongeForge was meant for and it is very, very annoying to not be able to use a mod that SpongeForge said that it would allow.
Why?
OTG and the presets it provides is one of the most popular world generation mods out there and for SpongeForge to not allow it/cause compatibility issues is beyond ridiculous. Although I do not see a possible plugin that will be able to accomplish the same task as OTG with the presets it provides, I do see a patch being made for OTG from the Sponge Powered team to allow OTG to work properly.
Summary
By the way, I know it is difficult but I appreciate the work the Sponge team has put into this and to make an amazing core for our servers to use. 