We've tried just about every combination of mix constituents possible over the years and found the current one which we've used for over twenty years, gives us the best combination of water retention and root aeration under our growing conditions. We did try rockwool as a mix constituent a couple of times, and found no improvement in slipper orchid growth so we discontinued it. That's not to say that it wouldn't work as well or better under different growing conditions. There's an old saying; "What works for you, works for you". If your plants are growing well for you, the worst thing you can do is start changing any of the growth variables on a large scale based on someone else's experience. I think we all tweak things in small ways once in a while, chasing the elusive perfect growth rate and it's one of the ways we learn what works best and what doesn't. That's why Slippertalk is such a great resource - you see what works (or doesn't work) for a lot of other growers and then selectively apply some of these ideas to your own situation.