The system in place already makes it so when you create a roleplay, you have linked IC and OOC threads rather than having to make two separate threads yourself. Go take a look at any RP that exists right now, look at the top above the first post: those tabs are separate but linked threads for those purposes. Mahz has also stated that he intends to make it so people can create their own tabs for their RPs, so you should be able to emulate the whole separate thread shenanigans as you like once that's put in.

Keeping it minimalistic and intuitive at default is best though, so I doubt there'll ever be a thing like you're describing where you have a variety of text boxes presented to you when creating a thread and then having all of those sub-threads made automatically at once when you hit submit. It'd be annoying to have a ton of extraneous thread things (info, rules, sign-ups, characters, etc) if you only want to use the two basic ones, so it's better to just give those and allow people to make whatever other ones they like. Might take a while for that to be implemented though, so you'll have to tough it out until then.