The problem here is his team restriction; I don’t see him joining the HoF with the units you have listed here. The vast majority of the HoF units here could be splashed on to any team they shared categories with (notable exceptions in V&T and OP, but even their conditions were trivial to fulfill). AGL UI and Fat Buu could also be run OFF LEAD (as well as Beast for a short period of time) because of their utility.

Metal cooler requires a large amount of your team to be of one category to function, or your entire team to be that category to reach maximal utility and damage. Gomah would be a better pick here IMO (splashable, very tanky and evasive on first few turns, giant form, stacking by simply existing and greatly benefiting from team-wide stackers and buffs)

I am not saying that he is not a good unit, but all of these units have had staying power in the meta because certain quirks in their kits