The S197 isn't quite a crappy car that handles like a pickup truck. That said, whether the next gen will be "better" or not, what we DO know is, a base 2015 GT will sticker somewhere north of $30,000. I don't think this will endear the car to it's core fans, nor will it make the car more attractive to new buyers seeking affordable performance.
MSRP on a new GT right now is $31,095 which is north of $30,000, so your point is pretty much moot there. The new 2015 GT will be similarly priced to current ones with both exceeding $30k.
As for how the Mustang handles, I would like to point out that the Mustang is the ONLY car that Ford produces with Roll Stability Control. The only other vehicles that Ford makes that include this safety system are pickups and SUVs.
Roll Stability Control was created to help prevent trucks and SUVs from rolling over during emergency manuevers. Why do you think the Mustang requires a safety system made for pickups and SUVs and isn't used on any other Ford car?
Could it be because the Mustang is the only one using a pickup truck styled suspension underneath it, leaving it as the only Ford car with rollover vulnerabilities?