Pretty much the title.
Right now it changes all aura applications that hit you to hit 5 nearby allies on top of you (6 total), regardless of how many targets the skill providing the aura would have hit itself.
If it would be changed to 5 additional targets it would be the same to self application skills but would extend the targets to 10 on the shouts that already have 5 targets, instead of upping it to 6.
You then could make a support that gives regen and vigor to the whole raid and can be extended to either prot (earth traitline) or fury and swiftness (air traitline) or give condi cleanse (fire traitline) or take arcane for less 10man stuff but more 5 man oriented utility. You could react to the raids needs by changing a traitline, while not being able to provide everything at the same time => seems like good design to me.
Viable != Optimal
Not viable = You only get carried, 10 players with a build as "viable as yours" can't properly do it.