One thing I really like about this team is that you don't give the other team many set-up opportunities. Your only choice user is ridiculously powerful. I can't see any where that say, a SubSD Terrakion could switch in unless it was on a weakened Jirachi or Mamoswine. Your defensive core isn't particularly diverse, but it's very complete. Anything that Politoed, Tentacruel, or Jirachi can't handle are easily revenged by Breloom or Mamo. One place where I see a slight weakness is against stall. Facing up against stall puts a lot of pressure on Tentacruel to keep coming in and spinning. This is allieviated by the fact that you run Speed EVs on Tentacruel to toxic Jellicent before the taunt, but I think a well-built stall team would give you a headache.
Pokemon is an idea. A concept.