In my experience, the blade shape is what is the most important characteristic for a paddle. A blade that as a smooth entry in the water and does not create turbulence or suck air into bubbles along the blade is what you want. This smooth entry is what will enable you to reach high paddling cadence. Just reducing the paddle blade surface for this is the wrong way to do it, you lose too much power. small paddle blades are beneficial for people who are stuck with brands with non-optimal blade shapes (the ones that "bump" in the water when you try to paddle too fast for them)
If you do not race, you should also take into account your "natural" cadence. If you are more comfortable with a slow rhythm, a bigger blade will better suit you. If you race, well, you will have to train to change your cadence for the most efficient one...
For surfing, I am now using huge blades (but with a smooth shape and reduced blade angle: 5 degrees) to be able to take off in one or two strokes, and keep spare power available: Basically by rowing at 50% power (blade fully submerged, but moving it slowly) I still have enough power for normal use, but I know that I can instantly double the power if needed (balance chop, changes in the wave). Drawback is that bigger blades are heavier and thus less nimble. Also if you have spare power, you can use some for things other than propulsion: countering row for instance, with a paddle tightly stuck in the water, it is easier to bring the board around towards the paddle.
For comparison, here is the blade I use under a Kiaola Shaka'Puu