I'd hate to see the loss of Thunderhawk just on classic principal. I'd much rather see a park put some work into a ride like that than simply do away with it. I've still never quite forgiven Dorney for removing Hercules. The Comet at Hersheypark is still quite old, but maintains great popularity with park goers.
As for the roughness of Thunderhawk, it's mixed. I've been to Dorney three times this year. The first two times, I was extremely displeased with the ride and thought it was extremely rough. (Seated in the same position)
Last month, I had the opportunity to take part in a commercial shoot for CF/Dorney at the park and I thought it was running good, if not great.
As with all wood coasters, there are many factors that go into making each individual ride enjoyable or miserable.