TD uses a very similar look aesthetic and design wise from his early courses to his latest ones - soft, natural, curves similar shaping irrelevant of what site it is thats what I am looking at from a fellow designers perspective which you probably don't understand. I have seen building architects use similar material and style on different building sites rather than experiment and do something different.
Sometimes to be ahead of the game you have to evolve - Frank Lloyd Wright is an example his early buildings are different to the one in his later years. If you are comfortable in what you do there is an element of risk that if you will end up being left behind others who over takes you I think thats the risk TD has. 10-20 years time could be a different clientele who are more like the computer game generation they will probably want some thing different.
Do you actually have a good sense of how Doak's style has changed (or not) across his career? I mean, did you see High Pointe or Black Forest, then Pacific Dunes or Cape Kidnappers, then Old MacDonald, Tara Iti, or the Loop?
I certainly haven't seen most of what he's done, but I have seen a half dozen of his courses and from different periods in his career. And to suggest that there's little variation in the style--and not even across his career but in courses from the same period--is not well-justified.
Take High Pointe and Black Forest. Anyone would have been hard pressed to tell that these were designed by the same guy. High Pointe, save for a few greens was quite minimal. The bunker shaping was fairly simple. Black Forest was the opposite of this--wild greens, flashy bunkers. Maybe a bit too much at times given the hilliness of the site, but whatever its faults, you wouldn't say that it's similarity to High Pointe was one.
And neither looked like Old MacDonald or the Loop, which also don't look like each other. Old MacDonald has big, heavily undulating greens. The Loop's greens are smaller and most have less interior contour, with a lot of the difficulty coming from the slopes around the greens. Old MacDonald and Black Forest both had very undulating greens, but they weren't too similar to each other; the former were larger and more free-form while the latter were smaller with some steep slopes.
As for all of the curves being soft and natural, what are you looking for here? Square-shaped mounds? I know square-shaped greens came up earlier, but I fail to see how a lawn mower running in a line, then stopping and turning to change direction vs. one that runs continuously in a curve makes for something either substantively different or interesting. That Doak et al's shaping seems soft and naturalistic seems to me to be a major virtue--wherever they work, they do a good job blending the shaping into its surroundings. And you really downplay the difference in degree across his courses. Some, like the Loop are much more subtle with a lot of small contours. Others--again Old MacDonald--have big, bold ones. Hell, even the Loop has a lot variation within in big vs. small contours.
And I see one of Doak's courses that I mentioned at the beginning, Pacific Dunes, as being quite different in style from the others. It has the least-busy greens of all of Doak's courses that I've seen (huge contrast to Old MacDonald). The emphasis here is on playing angles. Most of the greens are narrow and deep, so it's critical to be in a certain spot in the fairway so that you're not playing into the green from a shallow angle. It's a good thing too because with the challenge that this imposes on iron play and the windiness of the place, heavily contoured greens would be too much.
Whether any of this makes him a pioneer, I don't know and don't really care. But if you want to argue that this is a lack of stylistic variety, well I think that's pretty much wrong.