Harmony will be lead by Sparkbeat, I suppose. And Jazz Hands HO team will be lead by Focus Sash Mamoswine or Terrakion.
Personally, I think certain pokemon are easy to counter in OU (that's me, yeah). I remember my Misdreavus walled every Genesect that didn't run Iron Head (and as most Genesect ran Choice Scarf, it was likely). After paralyzation, Gensect was neutered as a threat. Tornadus-T was tested when I was using my Paraflinch team, so paralyzation also ruined its game. Recently, I've been playing Smogon Doubles, so I didn't see Deoxys D. In fact, I think it is easily beaten by a faster Taunt user (Whimsicott) or just something that can OHKO-2HKO it (looking at you, Choice Band Victini).