bottomroller, I'm not very fond of most of the stream improvements that I have seen either, because many simply don't look natural. I'm also not very familiar with the limestone streams having fished freestone streams most of my life. So, my opinion doesn't mean much on this one and I know it.
But I'm keeping an open mind anyway. I've never been there, but from what I had seen in pictures and descriptions, what was there before these improvements was hardly natural. It was an improvement over the hatchery days though. I look at this as a continuation of taking out the hatchery and correcting issues created over many decades.
As far as why brook trout? I'll admit I favor brook trout, and I don't really have a dog in that hunt because I have never been there. But when you or anyone asks why, I have to ask why not brook trout? If it was predominantly a carp fishery, would you object to habitat changes that would favor brook trout? I'm not comparing rainbows to carp, just saying....
For some reason, the Browns never took over this stream when they took over so many other limestone spring creeks, even when policy favored them (as it did on the others). there were plenty of big browns during the hatchery days, but the didn't take it over after the removal of the hatchery, either. Hmmm. Big Browns and Rainbows can be found in so many other limestone streams, some not all that far from that one. Why not have one that has an excellent brook trout fishery. You will still have some browns and rainbows to target. The uniqueness of such a brook trout fishery alone will be good for the economy of the area I would think. I know the way it was before, i wouldn't consider visiting and spending my tourist money. I can catch big browns and rainbows elsewhere. But if this works, I'll be sure to visit it.
Bottom line, the "improvement" were to make it a better trout stream, They made these changes and no more stocking (not even brook trout fingerlings anymore), and then they are just letting the stream determine what type of fishery it will be. Who knows, the changes might make it better for the browns or the rainbows. To me, it sounds (and looks) like it might. If the rainbows stick around, so be it, I'm Ok with that (more or less).