I do agree that SWSD could use a roller coaster. I hope the rumored coaster goes through one day... we're the only Sea World without a major coaster! And no, I don't count JTA. It's a start, but it's no Manta/Kraken/Great White/Steel Eel.
As far as info, Screamscape even posted the proposed layout, which indicated to me that they were at least thinking about it pretty seriously. But plans seem to have stalled, and are probably changed by now... if in fact they are even still considering it at all.