I have a hard time banning anything with HARD counters and some pretty nice checks. This thing has absolutely no way to beat Jirachi in the Rain. Magnezone doesn't care too much about it, as none of the fighting moves will subsequently KO. Jolteon just doesn't give a shit, Rotom is good along with any Electric type. Then shit like Weavile, Mamoswine and Scarf anything give him some trouble.
You're dead wrong on all counts. Let's a take a quick look at all these "HARD counters" you seem to have so much confidence in.
- Jirachi: Can and has been confusion-haxed to death in the past. As numerous users state above me, it's also pathetically easy to hit, then U-Turn out to a counter. The only set that prevents Torn-T from getting through most of the time is Specially Defensive, as Scarf and SubCM are both 3HKO'd by Specs Hurricane. The U-Turn factor is the biggest thing preventing Jirachi from hard countering the bird, though. Every competent user's Rain team has a Jirachi counter, and getting it in on Rachi is a piece of cake with U-Turn. It's also far too easily trapped and killed by Dugtrio, a common sight on Rain Offense teams.
- Rotom-W: 3HKO'd by Specs Hurricane after rocks, and easily worn down because of its lack of reliable recovery. As it switches in and takes rocks damage, hit it with a Hurricane, U-Turn out, and it's already down to 60%. Do that one more time, and voila, the "HARD counter" just died easily.
- Jolteon: Hardly viable in OU due to its pathetic fraility and lack of a decent movepool. It's 2HKO'd by Specs Hurricane, meaning it can only switch in a pitiful one time. Not to mention it's hard walled by Ferrothorn, which every Tornadus-T and its mother carries as a common partner on Rain teams.
- Magnezone: You flat-out lied on this one. LO Focus Blast is a OHKO on standard Magnezone. Superpower doesn't do the trick, but as others state above me, the majority of Torn-T use Focus Blast these days. Also, Dugtrio.
- Weavile: You're really reaching now. Nobody, and I mean nobody, uses Weavile in OU and gets it to work. I think I've seen maybe two somewhat decent teams that use Weavile in OU. It can't even switch into any one of Tornadus-T's moves, and you're claming it's a check? Try again.
- Mamoswine: CB Mamoswine's Ice Shard doesn't even OHKO Torn-T, whereas a Specs Hurricane or LO Focus Blast does the trick on Mamo. And if you're using Scarf Mamoswine, why are you posting in this thread and not chilling on Serebii?
All your so-called "HARD counters" don't withstand a simple one-on-one analysis.
Alexwolf, Jellicent and Mew are much better against your generic full stall team. Celebi and Roserade and the like are generally only found on semi-stall (think The Great Southern Trendkill-type teams). Mew actually handles Roserade anyways, and Celebi's Giga Drain isn't even doing half damage to standard Jellicent. I understand that situationally Torn-T could be better to have, but on the whole I'll still contend that the two aforementioned are superior stallbreakers.