While I am not a huge fan of the new Mustang, I can't support the idea that they're too expensive. In fact Ford has actually done a very good job in keeping the price down.
According to my window sticker, the base price on the GT was $25,840 in 2008. That means that the base price has increased $6,260 in the last seven years (or fewer since the base price was probably similar at least through 2010).
A $6,260 base price increase isn't my idea of "keeping the price down". Pony cars/muscle cars originated as a small to midsize car with a big powerful engine under the hood and a low sticker price. The idea being that the younger generation would have cars they could love and afford and enjoy.
For 2015, Ford is trying to turn the Mustang into something upscale. It's now getting out of many people's budget. I think it's a bad move. At one point Ford was selling over 100,000 S197 platform Mustangs annually. Why? Well, one huge reason was that people could afford them! Now it's hard to find a new GT on a lot anywhere for less than $35K and that's getting well into the range of many other nicer cars and even some nice slightly used Corvettes.