Heh, this team is pretty different than when I last checked it! It definitely looks a lot more solid now and there don't seem to be any massive weaknesses that stand out to me. I was a bit surprised to see Rotom-W here since Gastrodon was already an excellent Rain check, but looking at it now I kinda like the change. It gives you another counter to Tornadus-T, but means you aren't weak to Politoed + Dugtrio + Tornadus-T cores who annoy SDef Jirachi a lot. Replacing Gastrodon does make you considerably weaker to Thundurus-T, however, but luckily Jirachi is a decent check unless they run Nasty Plot or are Choice Specs, and Latios / Terrakion can revenge-kill it to.
Following on from Chimpakt's EV change, you should use an EV spread of 248 HP / 32 SAtk / 228 SDef on Rotom-W, as this allows you to always OHKO 252 HP Gliscor with Hydro Pump, and as Chimpakt pointed out, OHKO Tornadus-T after Rocks in the rain. You could also test out a Chesto Berry with Rest over Pain Split to give you a better switch-in to defensive Politoed, as this gives it a one-time use recovery move that cures Toxic poison. However, this is really just personal preference.