The answer from Tom Chilton was predictable -- without crowd control in its various forms, Arena matches become little more than DPS races. Crowd control (and its cousin line of sight) helps Arena fights take a little longer, and introduces viable strategies that are based all around controlling the other team. (As opposed to just blowing them to heck.) But the forums are alive - alive! - with complaints about Cyclone, Sap, Sheep, and hell, even Scatter Shot. No sir, folks don't like crowd control. Often, it seems like they'd rather get killed than sheeped.
I think it comes down to a pretty basic thing -- we have fun in these games by controlling our characters. Anything that jeopardizes the control of our characters on either a short-term or a long-term basis is therefore anathema. No one wants to stand there, helpless, while some Rogue performs their billionth stun on you. It seems to me (in my rosy-glassed retrospect) that we heard less complaints about insta-kill POM+Pyro than we do about a 3 second stun.
Your mileage may vary, but I think until Blizzard finds some way around that dichotomy -- CC is good for interesting fights, bad for fun -- we're going to continue to see tumultuous forum fights about the issue. I'm forced to agree with Chilton -- crowd control adds a layer of strategy and depth to the tactics of the Arena. Still, I hope they do something about it.