User blog comment:Linathan/Monthly Spotlight: Top 10 Units (as of April 2015)/@comment-25816013-20150501032309/@comment-26140304-20150501210727

Actually, the lack of those effects do contribute to overall ability. A very good example of this is Shera. She, along with other mitigators in the game, is essential to have in almost any squad, but is not helpful in Arena due to her BB being single-target. When I'm talking about overall ability, I'm talking about all aspects of a specific unit. This is divided into eight sections or less depending on the unit's form: Leader Skill, BB, SBB, UBB, ES, Arena, Stats, Usefulness.

As mentioned before, there are units that have lower overall scores, but with higher Usefulness scores. For instance, you would seek more uses for Quaid compared to Tora. In terms of judging certain abilities that slightly hinder their overall scores, those don't mean that the units are bad. Quaid and Ivris are excellent units. Like every unit in the game, there are bound to be some downsides to their abilities.