I just completed a list of hotels in Sharm that have at least one water slide. I got 34 all together, perhaps a few are missing, but I did check even near-impossible ones, like e.g. I would never had thought Sharm Holiday has one, or Gardenia Plaza, both very simple 3-4* hotels, or at the other end that Grand Rotana also has a water slide - thought they would be too posh for these things 8-), but then as even Hyatt has one... :-)
It begins with a review of all those new luxury Royal wings in Sharm but scroll down to the Aqua Park photo. The numbers after hotel names indicate its rank in TA Sharm "top" list - though some are debatable, then still it is a kind of indication.