Thank you both.
I tested out a 9' 5 WT Sage X and a 9'6" Loomis NRX+ (shop didn't have a 9' in stock) a few days ago during two 4 hour floats on the upper West Branch. I was amazed at how much more accurate my casts were at all distances compared to my long time rod (Sage SP, circa 1990s). I just looked at a target and the fly went there! The dampening technology has really advanced. ?That said, I can't say if the Sky G or Sage X would suit my casting style better. I tend to have a crisp casting stroke and I don't carry a lot of line in the air, preferring to shoot line for distance when needed.
On the long, flat pools where long down and across presentations are important, I also found myself struggling to mend or pick up line after a drift with the Sage SP. The Sage X had no such difficulties.
I did not like the Loomis as much, probably because of the extra half foot of length. It felt heavy and slower than the X. My buddy bought it anyway. I have no doubt the 9' NRX+ has a much lower swing weight compared to its 6" longer brother.
BTW, I have a decent 6 WT I'm happy with that is good for most streamers and indicator nymph rigs. So, the Sage X or Sky G would fill the role of dry fly and dry-dropper fishing at most reasonable distances. The biggest challenge would be casting and straightening 3/4 of a 14' 6x leader on a 60+ foot cast on big water into a headwind.
And, to falcon's point, the line choice matters a lot. I'm tempted to buy a cheap 4 WT line and throw that with the Sage SP to see how it acts.