Is it too late to join?
If it isn't, then I will be available for combat by anybody who uses Shadow Tag Gothitelle. I am making a team designed to seemingly "handle" it that needs to be taken on to see if it can deal with Gothitelle in practice. You'll know it's that particular team because I have two Pokemon named "Flotsam" and "Jetsam" in it. I do not plan on using Gothitelle myself, but allowing myself to be challenged by ST Gothitelle users alone will allow me to be able to handle the RU metagame better.
If it is, then I'll just go back to what I was doing, which is continued usage of Pokemon who are better than Metang in RU (read: all of them). I do look forward to seeing how Gothitelle handles the RU metagame, though. Maybe it'll make the tier more worthwhile, or it will cleanse RU/NU of a potential threat. I don't know, for I have not squared off against someone who used a ST Gothitelle before.
I have faced off against ST Chandelure in the upper tiers, and found it laughably bad, though. Considering Gothitelle is in every way a worse Pokemon even with Shadow Tag, I will keep a close eye on the poor unfortunate souls of the RU metagame.