Personally I think it should be merged with the Support parent forum if the software supports it. Subforums of a subforum are not very visible as evidenced by some of the Linux users in General Discussion threads not being aware of the threads related to Coherent_UI issues here. Also there are already Linux issue threads in the parent forum so it doesn't seem like the distinction of this being "The Linux Forum" is actively being enforced by the staff.
I think that Windows should have its own sub forum, and Linux should have its own sub forum and OS X should have its own sub forum for start-up issues. When you click on "Support!" it's easy to miss the "Mac and Linux Getting Started" Maybe there aren't Windows start-up issues any more, I don't know. I have Ubuntu 14.04 and about every other time I download the latest version and play, it doesn't work. There has almost always been a solution, but they are getting harder and harder to find.
Not only that, only Mac has a stickied known issues thread in this subforum! The consistency of our support infrastructure needs to be improved.
I have topic on Steam already so I decide to not create one here especially because I can't lock it for example.
I could post a sticky to link to your Steam thread if you want, or lock the known issues thread for you after you create it here.