While what you say is certainly applicable to Lae'zel, Karlach and Gale, I think this doesn't apply as much to Astarion (who is fine as is), Shadowheart and Wyll.
Not sure if you checked the Reddit post, but the initial pitch for justifying that Shadowheart could be a form of cryptic bard, garnerned over 100 likes and prompted several debates, some of which make sense, such as the Astarion Shadow Monk trope.
While I can see the risk of plying more on Shadowheart's background and less on her class could be seen as a risk to some, I don't consider my second ask of changing Wyll's nickname from "Blade of the Frontiers" to "Brave of the Frontiers" to decanonize him as a Blade Warlock is that much of a big of an ask, considering the fact that the end of the day - he is still a fraud dependent on Mizura to get stuff done.
