The Elemental is a 3/5 flyer for 4U. Whenever it attacks, you tap all creatures the defending player controls. That's a pretty sweet ability, actually, helping you to swing past big problem creatures. Since Sultai decks played huge creatures like Tasigur, the Golden Fang, Gurmag Angler, and Sidisi, Undead Vizier already, that tap ability can be a game-ender.
Then, if you happen to need to Delve it away, you can pay 3BB, 3GG, or 3BG to return it to play from exile tapped. It does have to be played as a sorcery, which is kind of too bad. Having to be played from exile at sorcery speed is probably why this hasn't seen more play in that Whip deck. It's basically been relegated to the sideboard in a lot of build to deal with Aggro strategies, but some players have mainboarded it with some success.
The big thing about Torrent Elemental is that it could survive Languish, the powerful-4/-4 board-wipe in Magic Origins that was a major removal spell in Standard for quite some time. It's really not a bad creature at all, and it seems playable. But, without Whip to bring it back from the graveyard, it lost a lot of its Standard competitive usefulness.
For awhile, this was a bulk mythic rare that vendors had high hopes for, and you could get them as throw-ins in trades to get some vendor store credit quite easily. Unfortunately, a new deck never emerged for the Torrent Elemental. But, it's still a good card that may one day find a new home.