Yea, maybe the flavor doesnt really work, but part of my thought process here is that only Arrest in the blue starter actually has any immediate impact, and even then, its only a stall. Most of the other starters have something that needs to be dealt with immediately or that gets played and has an immediate detriment to the opponent.
As a theme, blue is supposed to move slowly and build up threats or set up combos. Against black specifically, there are always easy answers to disrupt the combos, most notably, just keeping the blue board clear. Blue should be able to put up cheap defenders that are actually good at surviving, which on paper seems to be the design, given that the overall attack value of the blue starter is super low. The problem with having low attack values and high health, for 1, is sacrifice the weak. For another, defenders that don’t wear down the attackers just mean the opponent builds a board while you have nothing.
As someone once said, Tower is the secret 11th card of the blue starter, and its because of the super low atack values of the starter. Based on that, some defensive attack bonus would be appropriate, something like the ironbark treant but with a bonus to attack values.