Speaking about the physics, the one piece rod will be more sensitive due to the smaller mass of material in its construction (the ferruled joint adds mass). The smaller mass of the 1 piece rod increases senstivity. With that said, the difference may not be noticeable to the angler. You can only know using the exact same model in 1 and 2 piece versions.
I agree with the line making a huge difference in sensitivity. Braid can increase the feel of all rods. But a more sensitive rod will still be more sensitive with braid than a less senstivie rod with braid.
I also agree that 1 piece rods are less convenient. That is why there are 2 piece rods - in order to accommodate all anglers' situations.