This set isn't new at all, remember that Choice Scarf does not make a set "new".
If you were talking to me, this set isn't new because of Choice Scarf, it's new because it's focused around supporting and, in my experience, is amazing at luring and crippling Heatran w/ t-wave. Also, it can outspeed skymin in case they try to stay in on you.
EDIT: Reposting set since this is on the next page so as not to confuse those who read this post.
Rotom-h @ Choice Scarf
Modest
252 Spd/252 SpA/6 HP
Trick
Thunder Wave
Will-o-Wisp
Overheat/Shadow Ball/Thunderbolt/Discharge/HP (ground,ice)
This is my Rotom-h I've been using for a while. It's worked wonders for my team, being easily able to cripple almost everything. It's also really fast thanks to the scarf, reaching 406 Speed, outspeeding Skymin and scarftran with ease, in addition to most everything else. It can cripple attackers relying on sheer physical power with a swift will-o-wisp, those relying on their speed with a nice Thunder Wave, walls with a well-placed Trick, and many pokemon in general with a powerful Sp. atk. I personally run overheat because I need it for coverage on my team, but any of the listed options would work fine. The SpA EVs can easily be moved to HP if you want bulky rather than powerful or you could run calculations if you're looking for a specific OHKO and distribute them between HP and SpA as needed.
This Rotom is a great pokemon to switch into something, particularly when you lack something designed to take a specific hit, because it's insanely bulky, and can most likely cripple or kill the pokemon without any trouble.
IMPORTANT: I found out that the whole time I've been running this set, I ONLY had 252 EVs in Speed, no SpA or HP or anything, and it worked fine and was one of the more helpful members of my team. Now I can add a significant amount of power or bulkiness to it and it should be even more effective!
Please try this set out, comment, criticize, praise it, enjoy it.
I've been using this some more and i have a few thoughts. first of all, this guy's AMAZING for luring in heatrans, particularly if you come in on a fire-weak poke. This means whenever you switch into something weak to fire, you unleash a t-wave, predicting a heatran, probably scarfed, coming in. if you paralyze them, then they're practically useless for the rest of the game. Also, I find myself hardly ever using w-o-w because I'd much rather just paralyze something or crush something w/ overheat. This may just be because my team benefits quite a bit from paralysis, but either way i'm thinking of replacing it on the set with tbolt/shadow ball. Thoughts anyone? I recommend this to anyone looking for a decent speedy 'wall.' I use this on my team to absorb all kinds of things and throw around paralysis, which often sets up late-game sweeps for my azumarill.