I doubt Merlin would ever make a Splash battle again after building battle galleons at Alton. The queue for the ride is barely over 10 minutes and, although they're compact and fit in with Gardaland's target market, with little interest there would be no point in getting one. Also where's a small lake in Gardaland to build on?
To be honest splash battles are hardly thrilling and get you pointlessly wet, but what about a splash battle with coaster elements? (worlds first)
Why can't Gardaland build another big ride anyway? Dreamworld have done 2 in 1 year!