Though there are less top end bucks, there will always be 80 inch bucks even on a drought year (in Wyoming). Killing a big buck of that class is a matter of patience and time and sorting through a lot of bucks. Antelope horns start to grow in November, so antelope are probably the most influenced by the prior years drought of any western animal (as far as trophy quality). Reports are moisture had been fairly good more recently. The horn growth in 2012 I understand was off due to poor spring moisture. We still got a couple nice bucks.
My gut feeling is that 2013 will be fairly equivalent to last year as far as trophy potential (poor fall moist, which affect the tops of the horns, better spring moisture which affects the bases of the horns).
I am more concerned about future years (2015, 2016) due to reports I have been hearing about fawn survival. Antelope typically reach their trophy potential at 3-4 years old, so with poor fawn production/survival, the worst may be ahead.
That leaves the question, in a few years, will we wish we had hunted this fall or next fall. It's always a guessing game.
It is hard not to have a great antelope hunt in Wyoming, and I think WYF&G does a good job issuing tag numbers for the antelope that are available.