active sprint would mean it could be used in combat, which would aid in positioning and maneuvering, where passive sprint just means more map control and less punishment from a retreat, it also screws up combined infantry pushes as some units will arrive before others. active, and free but with a cooldown adds more tactical depth and strategic flexibility.
You really really don't want active sprint Obers. Between bundle and IR StG 44s and being almost impossible to close in on, it's a bad combo.
In any case, this whole discussion is moot imho. Ober combat performance is fine I think, just their timing was off (and getting buffed next patch). It's a 4 man squad facing artillery and light/med vehicles.