http://www.youtube.com/watch?v=j0VSS-rvfhg Is the serve at 9:51 legal? I've almost never been able to return this types of serve no matter what I try. I always lose critical points against this guy when he starts using this specific serve and I feel very frustrated and pissed off every time he succeeded the serve....
Nothing wrong with that serve except it is not good Flat and short trajectory, should be relatively easy to intercept. You just need to be quick to get behind the shuttle and then thunder down a smash right at the server.
It's just a really flat flick serve played with forehand (legal). Try playing something simple, if there is no time for a big swing to smash, try using your wrist or play a drop instead.
The guy in yellow in the near side seemed to be serving at his chest level every time. Or am I misinterpreting his upward racket movement just before the services?
Very legal. When receiving, hold your racquet so the the racquet is a bit higher and not so close to the net. Receive serve standing about 4 inches further back. That might help.
I don't find any issues with that serve in terms of legality.. It's indeed very flat, so keeping your racket a bit high will help. If you find having no time to react to this serve, try receive his service a step back from the usual-position.. (or you may stay a bit more crouched position, by which you will be able to see the shuttle much better, and intercept it.)
I've seen this serve being done before, but I dealt with it by standing back a bit (like what you guys said) to give myself a bit more time to respond to it.