It's been a few years since I've been there, but it'll be really interesting to see what they did with the greens. They have clearly always been very proud of the "fast" greens (and mention it again in the video), but I thought they were too fast for what they have. I have nothing against greens running fast if that fits how it was built (Kinloch comes to mind), but RCC's were on the small side with significant undulation. There was one hole location in particular on such a severe slope if you were putting uphill and missed it with some pace it would come all the way back down below the hole every time.
Small, fast, and undulating all in 1 package is not a good thing. There just weren't enough good places to put the hole. They obviously threw out small, so seeing what they did with the other 2 will be fascinating. Personally, I'd have leaned into the severe slopes like Southern Pines and run them a little slower.
Like the others here, I don't know anything about the breed of bent they chose, but choosing bent in the first place is noteworthy. Everywhere else nearby has gone to bermuda when renovated or built recently (Duke, Wildwood Green, Prestonwood, Old Chatham off the top of my head). If you're going for fast and tolerant of significant foot traffic, that's typically the choice. Even down in Pinehurst, the Ross courses are going to bermuda. My guess is that giving up on bent was a no-go for the members.
I lean toward agreeing with you about the relatively unusual decision to stay with bent grass during a renovation in 2020; it's pretty close to unique in this part of the country, for obvious reasons.
It may be that sticking with bent is because of the smallish greens and significant contours; Bermuda, especially downhill and down grain, just takes too many pin positions off the table. I can't prove this, but I think there is a world of difference between bent rolling 12 and bermuda rolling 12; there are some putts on bermuda that just really get away, and places that you just cannot put the pins, so unless they wanted to really change the greens, changing the grass might have been a non-starter.
As it happens, I played a CGA four ball at Treyburn on Tuesday; it's a McConnell course (Fazio design), still with bent grass greens that are just lightning fast. The putting was extremely difficult, and the penalty for being above the hole was death, but had those greens been Bermuda, it would have approached being unplayable. As it was, it was exhausting but possible. (BTW, I shot a million, but not because of my putting.)
The other factor that has to be taken into account with a McConnell course is that they just don't get much play, at least compared to Pinehurst. Old Chatham is probably a better comparison, as is Hope Valley, so in that regard RCC sticking with bent greens is still highly unusual, but it appears that McConnell is drawing money from a bottomless well, and can do anything he wants in terms of course conditions. If that wasn't the case, I don't think we'd be having a discussion of any work at RCC, because it wouldn't have happened.