Checked in yesterday (Nov 1) the first official day of the rebranding. Never stayed when it was Le Meridien, so can't make a direct comparison, but from what I've overheard from other guests, all the Le Meridien branding/ads/logos were replaced overnight. Can't speak for the renovation.
The owner of the hotel is Asset World, which is affiliated with the owner of Chang beer. Turns out the owner was at the hotel for the re-opening ceremony, so all the staff were on high alert and very busy. The GM was also on site directing things, and they even had an all-hands assembly for the arrival of VIPs with a professional photographer. On the exterior were some red carpet/bouquets, and there was a reception for a bunch of VIPs at the hotel restaurant, Ping.
https://www.assetworldcorp-th.com/en/home
Given the circumstances, it's understandable as a lowly Gold there was no upgrade. It was also unfortunate that our room was not ready until well after check in time, with no alternate options. What was actually surprising and delightful, was a "surprise and delight" card it appeared they were offering all elites, offering a choice of several options, including a "gift" (didn't ask what it was), 2 beers per day, 1000 extra points, 20% F&B/spa discount, or daily breakfast for 2. Took the breakfast.
The breakfast buffet (taking place at Ping) was actually quite impressive, including a huge variety of Western and Asian foods.
The room itself was fine. Small, with wall-mounted dispensers of toiletries and clearly some age despite the recent renovation, but everything in working order.