Bill, you've tried a lot more canoes that I thought when you initially said you've had the Dragonfly since 1988.
I hoped the Dragonfly 15 would have a similar balance, just more gentle with a slower leaning response.
Even though I personally don't recall paddling a Curtis Dragonfly but have paddled the DF 15, there can be no doubt that the DF 15 is more stable. It is 2" wider at the waterline and 1.5" wider at maximum beam. The original Dragonfly was designed as a whitewater racing canoe for Harold Deal in the combined class of slalom + downriver. The DF 15 has been detuned, lengthened, widened, and increased in volume to be a more comfortable and capacious river tripping canoe.
But it still has a roundish bottom, which doesn't bother me but may not be a sufficient increase in stability for you. The only way know is to water test, which is difficult from Colorado.
However, I do like depth when I have been out in bigger waves and want some leeway when leaning. I realize that also makes the boat more susceptible to wind.
Yes, that is a dilemma when paddling big, windy lakes and rivers: Depth increases windage but gives a feeling of security in waves. I assume you must paddle mainly in lakes if you are not running whitewater in the Rockies.
But note that the DF 15 is significantly deeper than the original Dragonfly at the ends. The bow height is now 21" vs. 17" and the stern height is now 18.5" vs. 15.5". The center depth is unchanged at 14". Therefore, it is reasonable to assume that the DF 15 will be noticeably more affected by wind than the original DF.
My problem with my Dragonfly has mostly been the dynamic balance with respect to wind direction.
The DF 15 has asymmetrical rocker, which often makes a canoe funkier in winds than symmetrical rocker. The original DF has symmetrical rocker.
For paddling on lakes in wind, you may like a change from a highly rockered, maneuverable canoe designed for whitewater, and instead try a harder tracking lake canoe with only modest rocker. My Swift Keewaydin 15 solo canoe, at 28 lbs. and with modest rocker, cruises nicely on lakes and is more wind balanced than my SRT, Wildfire, Caper, BJX, Bob Special, ME or Winisk.
I'd get a lighter version of whatever than I now have, but it has to be rock resistant.
I agree with Alan Gage that modern composite layups are plenty rock resistant for recreational flat water paddling and tripping. All of my seven composite non-whitewater canoes—which are various combos of S glass, Kevlar, carbon, and Innegra—have nothing more than a few bottom scratches, some after more than 40 years. My 1999 Hemlock SRT is built like a tank, S glass plus Kevlar, a whitewater layup really, which could not be damaged by any reasonable amount of tie down force.