I, too, want to see some sort of ASR system introduced sometime. It would add a little variety to the game and encourage the use of different types of planes.
I would love to be able to take off from a port or airfield in a PBY, or shoot off the back of a cruiser or BB in a Kingfisher, and go out and be a 'hero'.

The 'ghost' idea, which has been mentioned several times in another BBS, seems to be the best ASR option, IMO.
Another possibility for these types of planes would be some sort of recon function. Maybe ship-launched floatplanes could also serve as naval art'y spotters, too.
As for landing the ship-launched planes, I suppose there are at least a couple options. One would be to slowly advance on the aft end of a ship, simulating the USN's plane traps. Another would be to land along side a ship and get stopped by an arrester hanging off the side of the ship, Kriegsmarine-style. I don't know how the IJN, the RN or the Italians did it.
Kkoori mentioned a bunch of good A/C options. The A6M2-N can't be used for ASR, it's a fighter. Same goes for the N1K (which wasn't mentioned, but I figured I'd better deal with it anyway). I suppose one could throw in the Aichi E16A "Paul", the Curtiss SOC Seagull, SC Seahawk and SO3C Seamew, the Supermarine Sea Otter, and perhaps the Beriev MBR-2, just to make the list of options more complete.
I think you would likely see the PBY and OS2U modeled as the first flying boat and floatplane, respectively.
PBY is a classic (duh), and it could be used as a substitute for similar planes, such as the Dorniers and the "Mavis". Still, I would rather be in the more modern flying boats, such as the Sunderland, the PBM, Bv 138, or the "Emily", as they might be more survivable in the online environment.
The OS2U was the most produced and widely used floatplane of the war. Unfortunately, its seems rather mediocre compared to some of its contemporaries, such as the Ar 196A, the E13A1, and the F1M2. I would feel safer in the virtual skies with any of these three than with the OS2U.
I would love to see the F1M2 modeled!
Regardless, I'd fly these types of planes almost exclusively if they were included in the planeset. Of course, I AM sick in the head.

Andy