User blog comment:Mich, Michele & Kuhla/Future Units Preview/@comment-26917552-20160129054754/@comment-27631333-20160129222810

Yes, we are at a point in the game where all units could potentialy be useful. Lucina may not be better than Ark in terms of hit count buffers, but if her elements are going to be useful, then there is no doubt she will be the better choice, and then again, if another unit is providing the buffs, then she loses her advantage