and yes, they can actually build roads.
So, I designed this unit in a previous game. It's an upgraded settler (with a compass and telescope). So it gets 4 moves, better vision and costs just slightly more than a standard pioneer (due to the savings from the Conscript attribute).
Redesigning a unit like this works fine in the game in which it's designed. But when I started a new game and this unit was available, the unit doesn't have settler abilities anymore.
BTW, the magic that distinguishes a Pioneer from a regular unit is mysterious. Why isn't there a "Pioneering" attribute?