Its a little strange for this decision to be made based on a thread in Allo (if that's what happened) when pretty much the only ones affected are the people in Osteo, most of whom don't even know this thread exists. I only wander around Allo when I'm bored and the wait for the match is killing me right now, which is how I found this thread.
I'd like to see an Osteo thread from a mod detailing the proposed change in the Osteo forum, so all the people who use it the most can weigh in if that's possible.
I personally think things are fine the way they are, but a lot of that probably comes from the added annoyance an extra page click will cause me on the mobile version of this site.
As it stands now, Osteo is a forum I can click on directly from the forums page. If it becomes an Allo subforum, I'll have to click through Allo to get there, which is like almost the entire reason I don't like the idea of a change. I also think it will be harder for newcomers to find because of that, but who knows.