Well, the biggest problem with hitting more targets is that you actually need to hit those 5 targets to justify the normal ability being better than the SAW. The SAW has more general use and i'd pick it anytime over the normal skill. It hits 3 targets for more damage since she shoots faster and the recharge time is shorter. If i want to blast tons of targets with magic damage i have other options.

All in all, to justify staying with the normal skill you need to be able to use her ability to hit 5 targets consistently.