>>19789608>VGC has pokemon that are broken, yeah, but you get over that and play in the metagame that whirls around the broken piece of shitThere's really nothing that's broken in doubles, because it's ridiculously hard for something to be broken in doubles. Like, Kyorge is broken, because it has stupid levels of bulk, stupid levels of SPREAD damage and a great typing. Mega Mom, arguably the most powerful mon allowed in VGC, has good but not great bulk, can only single target, and takes neutral damage from everything except ghost.
6v6 singles, however, it's really much easier for something to be broken. Mega Mom is really, really broken. It can sweep your entire team without even trying and with almost nothing being able to stop it and with almost no support from its teammates. In VGC, it's centralizing in that "it's the single best pokemon and you really should prepare for it and consider using it." In OU, if it were allowed, it would be centralizing in that "it's the single best pokemon and you NEED to use it to be successful, or have half your team be able to check it."
Shadow Tag is not so great in doubles; in singles, it shot a PU shitmon all the way to BL (Gothitelle.) And then they gave it to something with box legendary-level stats, and there was basically no way to allow it in OU without it shitting on everything, because smogon wants a meta where offensive teams are not the only thing that can be successfully ran. Blaziken, really really broken in singles, actually pretty shit in doubles (HJK is like the worst move.)
Smogon actually has their own doubles format, 6v6. Besides box legendaries (minus Kyu-B,) nothing is banned. Not even mega mom. They even just removed sleep clause. It's not fair to compare VGC and OU formats, because they're extremely different and the people who actually make the pokemon have doubles in mind.