With improvements in power output (or drag reduction) only resulting in a ‘cube-root’ increase in performance, future progress in the design of boats or paddles are unlikely to produce clearly measureable improvements in ‘time trials’.
Identifying incremental improvements will depend more and more on the paddlers support team (coaches / sport scientists etc) being happy with the ‘science’ behind any suggested change, and implementing it on this basis. (We’re generally happy with the idea of a very clean boat hull, or careful nutrition improving performance, without really being able to measure the improvement. We ‘know’ it exists).
I’m using this site to put forward some thoughts on how performance gains might be achieved. Mike Phillp, Feb 2016.
contact mikephillp@btinternet.com
Articles :-
Paddle Comparison Tool (The Genesis of the Physic Paddle)
Optimum Stroke Rate (Paddling Cadence)
Marathon Weight Boats & Sprinting (High Inertia Boats)
Wings, Bernoulli, and Blade Locking
The Advantages of an Adjustable Paddle Shaft 
Effects of Blade Size on Performance