The argument about vane size and shape has been raging for years all over. In my opinion it all comes down to three things: cross section, balance/spin, and clearance.
Cross Section: The surface area of the vanes on which wind can contact to push an arrow off target. This one boils down to the amount of material that is stuck to your arrow. A 4 inch low profile vane and a 2 inch tall vane have almost the same cross section size. So they both have about the same amount surface area that wind can act on.
Balance/Spin: Longer or shorter vanes can effect the front of center (FOC) balance of your arrow by changing where the weight of the vanes falls. Shorter vanes tent to move FOC back more than longer vanes. The amount of spin the vanes can put on the arrow is directly related to the size of the vane, the longer air is in contact with the vane the more it will spin the arrow. This is a lot like cross section. Long, low vanes and short tall vanes do about the same job because there is about the same total interaction on them.
Clearance: This is becoming more of an issue with full capture rest. Super short, super tall vanes don't fit through a lot of the full capture rests. This can bite you in the butt after you build your $200 new dozen arrows and then they don't go through your rest.
To sum up. With todays new bows, arrows, and other technology, vanes become a matter of personal choice and what works for you the best. I run 5'' vanes on some arrows, 1.75'' on others.