Kevin,
I like, own and routinely use all the camo patterns you mentioned, along with ASAT, Max 1 and some others. For the sage hills I often hunt in western Oklahoma, Max 1 is nearly ideal. I also used Max 1 shirts exclusively the two times I was hunting buffalo in Australia, and it was a great pattern for the area I hunted.
You're also right about not needing Kuiu or Sitka for whitetail hunting in the flatlands and about finding other clothing quieter or warmer than most of the Kuiu and Sitka clothing. On the other hand, my Sitka Kelvin jacket, vest and pants that are worn as mid-layers are very warm, comfortable, compactable and light-weight, making them very nice when traveling, especially by plane. I also have a Kuiu Spindrift jacket that is similar to the Kelvin jacket and some Core4Element prototype PrimaLoft insulated bibs that are similar to the Kelvin pants, except having the bib portion and an integrated outer shell. The outer clothing from Kuiu, Sitka and Core4element is not as quiet as the fleece or wool that I also have in my closet, but I personally have not had much of an issue with the noise factor unless I am walking around or happen to brush against a tree or some other fairly hard surface, and they don't tend to pick up vegetation like fleece, wool and other fuzzy clothes.
Sitka has developed several clothing items specifically aimed at the whitetail hunter in cold weather, and the Forest Optifade pattern was designed, in large part, to satisfy the demands of whitetail hunters, who comprise the majority of American big game hunters. Actually, my "mountain" clothing with PrimaLoft insulation is about as warm as anything else I have, and I have already paid for it, so I don't mind using it for flatland hunting too. But I also use other less expensive clothing for whitetail hunting, like you do, and those clothes work very well too -- sometimes significantly better in certain conditions.
Heck, I have more clothes for hunting than most people have for all their clothes combined! :D It usually takes me a long time to get my gear ready for a hunt, not because I'm trying to get everything packed, but because I'm trying to decide what are the fewest items I need that are best for the conditions I will probably encounter.
Allan