I've noticed on my Resto Druid that the GCD after shapeshifting is longer than any of my other spells. It seems that my Haste is not effecting the GCD after shapeshifting, where at 856 Haste it does lower the GCD to 1 second on all other spells. Does anyone know if this is working as intended?
I believe I may have found the answer to your question. In short, it's normal that shapeshifting abilities last 1.5 seconds and are not affected by spell haste.
I tested this interaction last year, and earlier this year I also recorded myself performing certain (physical) abilities and casting GotW:
Haste reduces the global cooldown (GCD) triggered by spells and certain physical abilities exactly as it reduces the cast time of those effects, but cannot reduce it below 0.75 seconds. The length of the global cooldown can therefore be calculated using the same formula given above.
Notice the word "certain" in the quote. This means that not all physical abilities are affected by it, which is important to remember because the shapeshifting spells are actually considered "physical" according to the game files:
Now, I must admit that my game knowledge is rather limited as I have mostly played as a feral cat, and I don't know in which cases haste affects physical GCD, but as far as shapeshifting goes, it's normal that the duration of the GCD stays the same.
In case what I wrote above is not convincing enough, here's a clip from Retail WotLK: