While I think isn't a great idea, the opposition to it strikes me as wrong-headed.
Firstly, it's like complaining before the original series started that continuing in a new city without any of the "Cheers" cast dooms the show from the start. and secondly, the series ended with Frasier leaving everything in Seattle behind to move to Chicago.
While I doubt there's not a chance of getting Laura Linney to resume her role (assuming he ended up with her), there's no reason this can't succeed -- providing the showrunners are as creative as the original staff and the survivors of the "Frasier" cast are willing to do guest spots, as did the "Cheers" cast.
--Dave Sikula