Are there any long term plans to merge the two forums? I understand the Site Feedback forum was a way to handle all the Discourse questions during the change over. Anyway, just a suggestion not a complaint
No, there is no plan to merge them.
Site Feedback was one of the categories that came with Discourse and it is monitored by some Discourse folks. It’s best to keep all of the issues specific to the software in Site Feedback. It’s not just for questions for our users, it also is feedback to the developers about the software. If there is something that you don’t like about the way that the software works or there is some feature that you would like to see implemented, you can post it there and the devs will at least look at it.
The version of vBulletin that we used to use was no longer under development and never had any devs looking at it for software issues, so there was no need for an equivalent forum there.
I do think, however, it might be useful to modify the decryptions of each forum a bit to make this more clear, as a lot of Site Feedback winds up in ATMB as that’s where we would have put it in vBulletin.
From 128 to 129?
Ha ha. 
No clue how I wrote decryptions and not descriptions.