Hi Kit - welcome to non-lurk mode.

From reading through your post, sounds as if you have 3 major complaints with your current bike - leg soreness, seat pain, and road vibration.

Regarding the leg soreness, have you had any kind of bike fitting done? I would expect some leg soreness after a ride that was a lot longer or harder than your usual rides, but I wouldn't expect it to happen all the time. If it does, it leads me to believe that there may be some fit issue you'd need to address - saddle too high or too low, too far forward or back in relation to the cranks, etc.

As to seat pain fit your fit/position can cause issues there too, as can having a saddle that just isn't right for you. I personally had to go through 6 different saddles before I found "the one."

If you do decide to get a new bike, it will still be important to ensure you have a good fit and the right saddle, otherwise you may still experience issues.

As for the road vibration...I don't think the different geometry of a road bike alone will help with that, but material will. What I'm not sure of is, for vibration-damping purposes, would it feel smoother to ride an aluminum frame with all contact points (seatpost, saddle shell, bars, or even cranks) made of carbon? Or smoother to ride a carbon frame with alloy bars, seatpost, etc.? I know a couple weeks ago I was riding my bike (carbon frame & fork, carbon seatpost, alloy bars and alloy cranks) on a rough chipseal surface and my hands & feet were almost going numb from the buzz - they were touching alloy, not carbon. My butt on its carbon seatpost & saddle shell didn't feel it at all. So maybe you'd be happy sticking with aluminum w/carbon fork, but upgrading your seatpost & bars to carbon versions. I'll be interested to hear what other folks here have to say on that.

I've also heard that the type of tires you roll, along with what pressure you pump them to will make a difference in how chip seal will feel - but I don't have enough experience with different options to make a good recommendation here.