This boat doesn't feel like 21.5" width at all, it has excellent primary stability and excellent secondary stability, the only draw back is lack of speed. It feels like a dead weight when you want to paddle fast, maybe all 16 footer are like that, that I just cannot say.
Overall, I am very impressed with this boat. If you don't do expedition, you definitely should demo the Capella 161
We have NDK Explorers which we would not trade for anything! But this boat is fun! Both found the outfitting to be good. Some friends who tried our boats did not like the rise in the seat bottom.
I found the outfitting to be extremely comfortable and can paddle it "off the rack" without any additional outfitting at all. Because of its maneuverability, it definitely needs the skeg that comes standard. The only time I used the skeg was in following quartering seas on a 1 mile crossing and it made life much, much easier. With the skeg retracted in those conditions, I needed to do an asymmetric stroke (sweep downwind, power forward upwind) to stay on course and that gets tiring.
The carbon/kevlar layup is light, but if I were to buy one, I'd go for the more durable glass layup as I don't treat my glass boats any different than a plastic boat and the extra durability is worth a few extra pounds to a boat abuser like me.