FWIW,
I paddle a Bell Magic. I use a Bending Branches bent shaft, and I won't leave home without it. I feel comfortable with it on lakes, streams, calm or choppy. I appreciate the tradition. (I also use a traditional Duluth pack.) That said, a couple years ago I was enticed by a kayak. Did the whole test paddle routine and finally made a purchase. I also spent some time with a very experienced yakker who taught me the do's & don'ts. Surprise, surprise...there is a proper technique for a double blade just as there is for a single. There's a learning curve, just as for the single. (I should mention that I have an 18 ft. touring kayak, not a 9 ft. plastic whitewater playboat) So when I started using the kayak paddle with my Magic, it didn't seem awkward.
I spent 8 days in Quetico this summer, and used the kayak paddle 90% of the time. I   was able to very easily keep pace with a tandem.
I guess the bottom line for me is: it is just like learning to use any other piece of equipment. Am I less of a traditionalist because I use a stove instead of a wood fire? A nylon tent instead of a canvas? Modern fabrics instead of wool? I  think not.
Give the double blade an honest effort. If you like it, use it. If you don't, abandon it.
Respect others' choices, but do what works best for you. And just have a good time!
;D Wind-in-Face
PS. Fishing is strictly a single blade job!! (At least for me)