any bike w/ 23 mm tires will feel like a rocket ship compared to your current ride!
tire pressure will be almost double so they will feel rock hard. your rolling resistance will be at least halfed.
your big chainring on your current bike will only have 3 or 4 more teeth than the small one on a road bike, so your gearing will be made for speed not climbing.
a roadbike will be atleast 10 pounds lighter than your expedition and your body position will put less pressure directly on your tailbone and more on your wrists, plus you'll be more aerodynamic so no more wind blasting you in the chest.
I recommend you make the switch asap.