Tamper with an old favorite at your peril, but there was a collective sigh of relief when the hotel revealed a more than $55 million renovation a couple of years ago: lighter, brighter, the very model of a sharp, slick, sophisticated beach retreat, and still in the island’s best spot. Guests continue to come in drove; these days it is not uncommon for three generations from the same family to arrive simultaneously. Now Mauritius has the greatest concentration of five-star hotels of any island in the Indian Ocean and yet Le Saint Géran has in no way been overtaken.