Spin and stablization are good things, but only to a point. Consider...

What makes the arrow spin? The air flowing across the surfaces of the fletching. What makes the air flow around the fletching? The arrow's movement. What makes the arrow move? The energy it gets from the bow string. That's the only energy source for the arrow, meaning the arrow has a finite amount of energy when it leaves the bow. Part of the energy it leaves the bow with is being used to make that arrow spin.

Say we shoot identical arrows from the same bow - with identical fletching size and type, one with moderate helical and the other with a very tight helical - the tight helical, rapidly spinning arrow arrow will burn up energy faster during it's downrange flight and it's forward speed will decay faster than than the slower spinning, moderate helical will. To say the same thing another way, the faster the arrow is made to spin, the more energy is used up to cause that spin. The more energy going into making the arrow spin, the less energy is available for the arrow's forward motion, downrange speed and, for a hunter, penetration.

That's not to mention that getting an overly tight helical can actually reduce the fletching's effectiveness by the front ends of the fletching diverting a good portion of the air away from the rear surfaces of the fletching. The fletching begins to act like a parachute instead of guidance surfaces. Along with the excess drag, you get those annoying flapping, hissing and whistling fletching noises.

Also, nowadays most guys are using light, small diameter carbon arrows instead of heavy, large diameter aluminums. Lighter and smaller diameter means the arrow is easier to spin, due to less rotational inertia. Using a 400 gn GoldTip XT and a 530 gn XX75 2315 as examples, it takes less fletching area or less helical, maybe even both, to induce the same rate of spin in the GoldTip as it takes to get the 2315 going.

I wish I could remember where and when I read the article, but I can't... It was the published results of wind tunnel testing on just about every fletching configuration you could think of.