Regardless, 8201 is, in my opinion, more than enough to get it into BL, at least.
That's not exactly how the tiers work...
Pokemon go into BL because they are too strong, not because they see a lot of usage.
However, if Rotom-X sees a lot of usage, it will become OU and skip BL completely.
Also, if Suspect Ladder is testing Deoxys, why is Shaymin S banned there? I can't find the reason inf PR.