Yeaaa.....
So, to expand more on why explanation/communicating across the reasoning is important, it goes back to what is the purpose of a tier list in the first place. They're primarily for readers interested in learning who's good or who's bad, right?
Here's the catch: if a person is asking that question, that means it is highly likely that he has not yet developed an evaluation process. So just learning 'what' is good or bad still leaves the 'why' blank*, which in turn can screw with the 'how (to use)' aspect sometimes.
And secondarily there are the readers who know the system fairly well already but are interested in other perspectives anyway. Ratings in a vacuum with no arguments given does nothing for this group.

*it's like when someone asks 'is Ea any good?', and we basically respond with some variant 'nah, she's terrible in most situations' and then just leave it at that. Offering a reason or two may offer some more help to the person asking the question here. Though Bear did cover the end game situation.
(and the basic reasoning I can offer for the reader is that a lot of Ea's value is derived from that maximal damage against stunned enemies buff. But it turns out that a lot of content is designed such that stun mode happens so late into a fight, such that said buff doesn't actually do much to change your probability of winning. IE typically, by the time you've hit stun mode, you're past the threatening part of the fight.)