the casino even without local punters will be a HUGE success. Bangkok is the most visited city in the world and all the foreign nationals would flock there to gamble.
the locals would go there too for the restaurants/bars/events. I imagine it would become essentially like a giant mall/entertainment complex, but the advantage of this one is that it is open after 10pm, when all the competitors close. The Thais would flock there to just hangout and socialize indoors.
Think about an Icon Siam, but open 24 hours, with booze and events and gambling.
Whoever gets this done, is going to make a killing.