North Carolina, Virginia, Virginia Tech, Duke, Miami, and Georgia Tech are all full of students from the northeast, and each has many alumni in the northeast. I would agree that this is not really the case with Clemson, NC State, and Florida State. One of the reasons Boston College joined the ACC in 2003 was to recruit students from the southeastern Atlantic states. I know that Syracuse, Pitt, and Notre Dame all want to do this as well because demographically it makes the most sense.
As far as the ACC having the old Big East bolted on, Miami and Virginia Tech are assimilated very well. Boston College has had more of a challenge, but with Notre Dame, Pitt, and Syracuse, it will help them. Connecticut would help even more. I can't speak for Connecticut, but I would think the UConn fans would enjoy all the good basketball competition that would involve rejoining Syracuse and picking up the Carolina Schools to play.
You can make the same argument for the Midwest schools. In fact, I would argue the Northern schools in the ACC are much more out of place than the Eastern Big Ten schools in terms of cultural compatibility.
I really don't see how you can fashion yourself as a "old school" ACC guy when the original ACC teams don't even make up the majority of the conference anymore.