Do you have a source for TWWHD being made in only six months? The game was revealed in January and released in September, so the development cycle was probably closer to a year.
Yes, the base Wind Waker game has aged better than Twilight Princess, and more work was put into the TP retextures...
I'm pretty sure the Gamecube versions of both games have the same Metascore, and TWW is higher rated than TP Wii, so I'm not sure that argument ever existed. In the end, TP HD's critical reception is simply an indication of the lower effort put into it compared to the other 3D console Zelda...
I find it amusing that Gamespot gave a higher score to TP HD than the original Gamecube and Wii versions. I wonder if it's partly in response to the outrage over the original score all those years ago. Still, nice to see fairly positive reviews all across the board even if the overworld...