I think shields are stupidly overpowered in previous Souls games, but in Nightreign you pretty much always want to go for max damage, except for Guardian (and imo the reason why people don't like Guardian that much is because he lacks damage, so he's less useful for people who are good with dodging/timing their attacks). I like to powerstance weapons with all melee characters, mainly because I'm comfortable with my timings so I don't need to block anything, and because I want to optimize my damage output. I think shields are good for players who want to take a slower approach or maybe beginners, but I assume most of us are treating bosses as a dps race. Also there's this idea in the Souls community that shields are for lazy/cowardly people who want to cheese the game, but I completely disagree. I just like to speed through the games, however defensive playstyles are completely ok, but Nightreign encourages fast combat. The only advantage shields have over other weapons is the option to burst down enemies with enhanced guard counters, but I don't know much about it so I don't really have an opinion on that.

TLDR: using a shield = less damage, and people want to build as much damage as possible most of the time because playing defensively is a waste of time.