210USD is more than what _I_ usually pay for very decent 4* or decent 5* hotels in SIN. The location certainly is VERY good, that's definitely not making it cheaper.
Roughly the same area, I would say for a 4* boutique hotel (small room but with pool, breakfast) around 130-150USD would be a good price. So you didn't really overspent that much.
What I mean with "_I_" above is that I (just as many FTers I would assume) are spending a lot of time or having automatised tools running through hotel price comparison websites, and eventually booking really good deals. If I wouldn't do that, and simply went along with Tripadvisor, found a hotel in an area I wanted to stay, and booked it, I would probably end not much below that. Now take in consideration it's on top of the list at Tripadvisor, and they WILL charge a premium.
So in short, yes, you paid too much, but you weren't fleeced or anything like that. If you want 5* hotels (and not 5* rated - BIG difference) then search for them.