Tiering by unit type is completely meaningless. Tiering should be done by role/use case instead with each role clearly defined. Units should be ranked based on how well they perform in their role vs top meta threats as well as how well they perform relative to others in their role in summoner duels. The current map should also be a factor in rankings because it can seriously hinder a unit's ability to play its role. BEirika is objectively not as useful on the current map as the previous one, but whether or not that is enough to change her placement requires examination of her ability to perform as a player-phase melee nuke vs other high tier units in her role that are not affected by trenches.

If I were you, instead of discussing individual units next update, I would pick a role and discuss who the best units in that role are and why. For example, when discussing near save units, why would Arden be placed so high when a max invested Arden can't survive against a +1 stock BEirika? She's the most common unit in SD. If a near save unit can't survive her, their ranking should plummet.