Slim: There's nothing wrong with the cassette; it works just fine. I personally don't like the large spacing between the gears. I think I just got used to the gearing on the triple on the road bike. My Synapse is a compact double and I don't find it much different than the triple.
Why I like road bike: Hand positions: I ride mostly on the hoods. With my hands on the hoods I can shift or break without having to move my hands to a different position. I also prefer the more aero position of the road bike.
Zenmaster: There are lots of road bikes out there. You'll want one that is less aggressive and gives a more upright riding position. If you watch a cycling race on TV, you'll see the riders have their backs parallel to the ground. That's got to be uncomfortable. I bet I ride at about a 45º angle on my road bike on the hoods. Some road bikes are designed to accommodate that flat back and others give a more relaxed position.
I see a lot of people here who purchase a hybrid, enjoy riding and quickly want a drop bar road bike in six months. Since you already have a comfort bike and are looking to spend some serious $ on a new bike, I think you should consider what bike will meet your cycling needs over the next few years.
Are there any LBS near you that have bike rentals? You could rent a road bike for a day and really get a good workout on it.