The thing about making Bane hit more targets, is that it won't take much to enable SMN to out-dps BLM in every respect, in every situation.

As it is now, SMN falls short on the AOE DPS front on stuff like WPSR, where you have to AOE 8+ targets on a routine basis. They make up for it on the bosses.

If you make Bane hit more, or unlimited targets, SMN will out-DPS BLM on everything. The only reason you would have to play BLM would be 'unlimited mana', which is a non-issue if you use Aetherflow properly and don't spam Ruin II.

SMN is in a good place from a balance perspective, and if you improve anything, it shouldn't be how many targets Bane can hit.