Ok after a few more games i realized that Ferro in rain is a huge bitch. One more reason to replace Latias with something that deals with Ferro better. I found that Celebi with Leaf Storm / Giga Drain / Grass Knot (i use Grass Knot, which OHKOes BandTar after SR most of the time, while with Leaf Storm it could trap me at -2), Psychic, HP Fire, and Recover, Modest with max SpA, 263 Speed and rest to HP, and LO, puts huge pressure into most offensive and balanced rain teams that lack Jirachi or Blissey / Chansey (many of them). Celebi can threaten every single poke found in such teams and with clever play Ferro can be handled too. If sandstorm is up and Celebi is in the battlefield the opponent will think twice before bringing Toed in, making Ferro unable to switch into Celebi at all. If for some reason Toed manages to come into Celebi, then you can still predict the switch in to Ferro (pretty obvious) and switch into Gliscor / Ttar / Terrakion and do your stuff.
Part of the OU QC team, message
me for a check!