Great Crossbows are surprisingly strong now, if you take the Rogue's Mechanic tree. Problem is, although it keeps up with repeaters on heroic levels, by the dawn of Epic and throughout all of end-game, they fall off into the abyss, because there isn't a single named Great Xbow.
Even if they will never be taken by min/maxing pros, I'd still like to have a choice of Great Xbows to play with. Frankly, I don't get why Mechanic would grant these abilities to non-repeaters and Greatbows, if you're not gonna have at least a bit of support for characters who want to focus them.