That is way flamethrowers have awsome potential, I once had a 10 man squad of Screaming legionaires, with a golem and a flamer. Only the flamer got any kills, and I still managed to come out ahead on the points for the squad (My opponent had some very unfortunate paradeploy results that put two squads of airborne rangers in a position that I didn't have to move to get any of them at all). I think the elimination of the roll is balenced in play where out of ammo and jams aren't a factor. Since criticals and fumbles are equally likely and have both been eliminated. However in scenarios or games with environmental effects where weapon malfunctions/out of ammo is a factor that a roll should be required.
I once lost a game played in level 8 environment conditions, where my opponent defeated me merely because he sat his Jungle Kommnado's on wait with 6" of visibility. As soon as I ended an action in a position that I could see him, he'd come of wait and shotgun me, my poor clansmen never had a chance.