In all honesty, I'm not entirely against the idea of Sea World doing a fountain in the main lake. Since they axed the ski show and tried replacing it several times with various things, nothing has really captured the original 'must see this if you go' mentality that the ski show had - it was iconic, much like Police Academy was for Movie World.
Now, to be honest, bringing back the ski show (or police academy for that matter) now would be a mistake - the world has moved on, and those sorts of shows are no longer enough to captivate the audience.
Instead, i'd love to see Sea World install a bellagio \ World of Colour style attraction in the lake. For me, Bellagio was a great attraction whilst walking down the boulevard in LV, and WoC was a spectacular night show. During the day, you can have it run regularly, and it would be the relaxing front of the park for people to enjoy, and relax. You could still use the lake for jet skis and such provided certain precautions were taken, or potentially the way Disney does with WoC and have elevating platforms.
It'd also be a great photo spot for holidaymakers (and weddings \ functions) but it would also give Sea World something to close later in the day, a final show before everyone goes home that draws people to the front of the park.
I'm pretty sure we have discussed this concept before, and I think one of the bigger problems with it was the salt water in the lake - but I can't imagine it would be that big of an issue to resolve.
Of course, this isn't me saying do a fountain instead of a coaster \ flat ride \ etc, but i'd like to see them do something awesome with the lake that didn't rely on corny slapstick humour, or a bunch of guys revving their jetskis up and down the lake for 10 minutes twice a day.