I was just there in September. It was where I got my OW and AOW, starting some nine years ago. The September visit was after a 4 or 5 year gap.
The thing about the island is that no matter what time of year you visit, it's like it's frozen in time, in the sense that the weather is about the same, the crowd is about the same, and the general "vibe" is about the same. Before arriving, I contact the dive shop for pickup from the pier to the associated hostel. On every one of my visits, five now, it's the same person confirming, the same pickup driver, the same person running the restaurant/bar, etc. On the September visit, the driver recognized me and asked how's it been over the last year /since/ I visited. I told him it's been 4/5 years!
The biggest changes I noticed are: one story buildings becoming two, more shops, more pharmacies and clinics (probably to service all the scooter accidents that have always been happening!), a new road connecting east and west sides of the island, and more families instead of just backpackers.
The dive sites are about the same in quality, though one site was definitely damaged by coral bleaching (lots of algae). Whale Sharks still pass by.