If you are a US manufacturer... Put Danny "Cha" Ching on a swallow tail, and watch them sell !!

My 2 cents on theory... It would reduce your tail lift... Bog the tail slightly....
Take a big square tail, like the 12'6 Fanatic, and custom cut it into a Vee tail (Swallow Tail).... I think the original would be technically quicker... But you never know, until you give it a go!