The RGB has a lot more individual domes than the R2. There are two fairly big sheets that cover most of the alpha section, some strips of three or four for the F key row, and then a ton of singles. The Type Heaven was similar, if I remember right, so I was surprised that the R2 had most of them in a single sheet. I'm sure that makes for much quicker assembly at the factory. The next time I have a reason to take one of these apart, I'm just going to pull all the domes and springs off. The alignment nubs on the slider housings make getting the domes aligned dirt simple. Trying to get them centered on the PCB and then flipping the plate over and down on top of the PCB has caused too many problems for me in the past.
I've put quite a few different sets of keycaps on my RGB. I've had Cherry-profile dye subs, OEM profile doubleshots (the originals and PBT versions), and most recently, extremely thick PBT SA keycaps from Signature Plastics. Those have been my favorites so far. They do make a difference in how the keyboard feels, but it's not drastic.
I do share your fear of LEDs burning out, so I really have no interest in RGB boards. I just like the Realforce RGB because you can put aftermarket keycaps on it. The downside is that Topre's housings are a little wide, and I've had a few sets that just won't work (they stick or make clicking sounds) without grinding down the insides of the keycap. I had to do that on the SA keycaps and on a set of Varmilo keycaps. I have another set of cheap ones from AliExpress that I love, but they won't work at all. They make all kinds of noises, but only on the RGB. They're currently on a Cherry G80-3000, where they work perfectly.