Another item on the great kayak debate list is the feathered paddle. Feathered paddles come from whitewater, and I wish I could tell you the exact history, but I am unable to locate something that sounds authentic. I remember once an associate explaining to students that it was to help whitewater paddlers transition from side to side faster, but I may be remembering that incorrectly, and if I am remembering it correctly, it may simply be wrong. The important thing is that it is not a traditional - historically speaking - part of sea kayaking. If anything it probably emerged in the late 1970's.
Greenland paddles are flat, and I think that is a good place to start for most paddlers for a few reasons. First it gives new paddlers one less thing to think about. It's easy. It makes learning the basic strokes like the draw and the brace and the forward stroke easier, as the paddle blades are behaving the same way.
I paddle with my blades flat with one exception. When I paddle into the wind, I will switch to a 60º feather, controlled by my right hand. It allows the blade in the air to slice through the wind, instead of being pushed by the wind. The headwind scenario is the only time I paddle feathered. The argument against doing this is that it makes you susceptible to a cross wind.
Though this is the reason I paddle feathered, there is also a reason I don't paddle feathered. If you paddle for four hours you will do about fourteen thousand paddle strokes. that means on just a four hour paddle you are doing fourteen thousand twists of your wrist, to control that feathered blade. I choose not to do this. That's not to say that there isn't wrist movement if you paddle a flat paddle, but it is significantly less than paddling feathered.
Surf paddlers don't like flat blades because the risk of the paddle being pushed into the paddler is too great, when breaking through the wave, though I was taught go head down with the paddle on the side of the boat when breaking through waves - essentially in the set up position for a roll.
I think the important thing in this situation, as well as the rudder or skeg situation is to do what feels right for you.
Follow your instinct. If your vision of a great paddler is paddling feathered then by all means pursue it. Just like the ruddered versus skeg question, a lot of this is personal choice
In Buddhism we describe intuition as 'insight that transcends explainable cognition' which translates to - trusting your gut. It is as simple as that. In Feng Shui we give all sorts of examples of how if something 'feels' right, it probably is for all sorts of reasons. Intuition is very important, be it choosing which set of waves will bring you safely to shore and which will thrash you about, or whether to listen to your gut about which paddle, or paddling style is right for you. You must learn to trust your instincts. At the same time, be flexible. If you have always paddled ruddered, maybe when you are seeking a new boat, or a bump in skill level it's time to try a skegged kayak.