Meade's advertisements for the 14-inch GPS state that it has the same bearings and worm gears as the other LX200 GPS models, so I suspect that it is indeed a stretched version of the same mount used on the 10 and 12-inch GPS models. The 16-inch costs many times more--triple?--so one shouldn't expect a 16-inch mount for a 12-inch price.
Another comparison worth making is not with Meade's 16-inch scope, but with Celestron's 14-inch. I have little doubt that the desire to compete with the C-14 line motivated Meade. So is it stabler than Celestron's 14-inch? The price is in line with a Celestron-quality mount, not a Meade 16-inch mount.
Bottom line: until enough of the new 14-inch scopes are in the hands of users for reviews to be available, we won't know whether the 14-inch is too big for the LX200 GPS mount, or whether Meade has hit a home run.