My kids find lazy rivers to be very, very boring, same with elaborately landscaped pools. The only thing that makes a good pool in their mind is waterslides and/or diving boards. Many of the pools listed in this thread do not have slides.

(Caveat that my kids swim on swim team 5 days a week, 2 hours a day and have acces to a HOA pool May-Oct, so just water in the ground does not impress them)