It'll be great to have more, and presumably higher luxury, options in Bangkok.
Erawan has a great service culture, so I expect that the PH will be even better.
As far as the opening date, perhaps some of you remember the announcements in late 2007 about the Park Hyatt Koh Samui? See here:
http://www.hotelchatter.com/story/20...yatt_Koh_Samui
Not only did it not open in 2009, it became the Conrad instead (SEP 2011).