The Gp sounds like a lot of fun to me. I honestly cannot wait until we hear more info about it.
As far as it being included in GTW, no, just no. Having it be a GP I have some real hope that they have worked hard to really bring out a good experience for the player (if this theme appeals to you.) If I am going to be guided by how much I enjoy Spa Day, then I am really hopeful.
It's funny because you are not the first one I've seen say that it should have maybe been included with GTW. I wonder, had it been, how many would be complaining that it should had been a GP instead so it could be fleshed out more? Hmmm...
