With the manual already available in the 5.7L R/T and 6.4L SRT, there is not a lot of engineering needed to put a 5 or 6 speed behind the Pentastar V6. It would boost sales that the base model manual trans Mustang is stealing away.
As for the new Dart, I like it and it is needed to get Chrysler into the booming small car market. I do like our Caliber and it gets 35.6mpg on the highway with a 2.0/CVTs trans combo. It is plenty roomy as well.
The Dart will be getting about 40mpg and will compete with the Focus/Cruze segment.
Back on topic, I wouldn't buy a V6 powered Chally. I would love an SRT8 6-speed myself, but I would probably settle for a R/T Classic with a 6-speed. I prefer the manual transmission in a performance car. And much like my 88 5.0 LX Mustang (5-speed), it would not be a daily driver. If It were my only vehicle and I had a daily commute with stop and go traffic, then I would probably go with an auto trans.