So basically, Praslin is an island, being smaller than Mahe, there are lesser activities to do, provided you know where to go and what to do.
So in this backdrop, if you stay on a property like the Constance Lemuria - a fabulous property with 3 private beaches, an 18 hole golf course, 3 categories of Rooms and whole host of things to engage in - it beats the dread of staying in an island like Praslin, and not having to wonder at what to do next!
You could simply engage with the Turtle manager to understand, all about the Turtle's on the property, go on walks on white sandy beaches, Dine at the private dining area of THE NEST (of course that comes at a premium)!
We spent just 5 days there and manage to do quite a bit.
Kayaking, Snorkelling, Sun-bathing, Cycling, Playing Tennis, enjoyed a Spa and what not.
Go there and spend a minimum of a week to enjoy the place, you would not have a reason to complain!