Now that I've gotten used to seeing cats so much, I can't say I favor one or the other now. Heck, wasn't one recent AC a cat vs. a mono? If parity could be somewhat ensured, I wouldn't mind a broad construction rule that allows for either.
I will say that when I first saw an AC45, it seemed kind of unweildy to me. Something I can't really pin down about the sail just looking too tall for the platform. With the AC72's, it seems even worse (at least with Oracle, which is the only 72 I have seen thus far.
I think it's getting to the point, for me, where the offseason between AC's carries even more excitement than the actual race. I'm already hungry to see the design rule for the next AC race after this one.
The first multihull to be in a race 1988:
"Forced to race, and lacking time for preparation, Conner and SDYC looked for a way to prevail. They recognized that a catamaran was not expressly prohibited under the rules. Multihulls, due to a lower wetted surface area and vastly lower mass, are inherently faster than equal-displacement monohulls. Conner, however, left nothing to chance and commissioned a cutting-edge design with a wing sail, named—as his 12-metre yachts had been—Stars and Stripes."
"The two yachts raced under the simple terms of the Deed in September, 1988. New Zealand predictably lost by a huge margin. Fay then took SDYC back to court, arguing that the race had been unfair, certainly not the "friendly competition between nations", envisaged in the Deed of Gift. Ciparick agreed and awarded New Zealand the Cup. However, Ciparick's decision was overturned on appeal and SDYC's win was reinstated. Fay then appealed to New York's highest court and lost. Thus SDYC successfully defended the Cup in what observers described as the most controversial Cup match to that point. (The 2010 America's Cup was a direct descendant of the 1988 Cup, as it featured two gigantic multi-hull yachts and generated even more legal activity and controversy.)"