The term “best” is purely subjective. While I think the WA breakfast is really nice, certainly “the best” among Hilton propeties in Bangkok, I won’t call it the best in Bangkok, let alone Asia. I found the dining room design to be very uninspired as well.
Some people gush over imported cold cuts, local cooked dishes, while I really appreciate fresh coconut juice and mango. Bangkok bfast I found better than one in WA is Four Seasons. Not for abundance of food variety, but I really like the high quality of the (limited) offerings, the (relatively) peaceful atmosphere and the river setting. But THE one breakfast dish I found truly memorable is the French toast with a scoop of ice cream at Hyatt Regency Bangkok!