I've been feeling that the rock/paper/scissors thing isn't really working for defense as we can't see who's hit us and with what. I usually just pick one type of shield and leave it there. With attacking I definitely feel the desire to try different shots but with shields there's no feedback to incentivize changing strategy. Maybe a pop-up menu when you re enter brawl after an hour that shows you how many and with what you were hit with.
Even just a graph at the top showing global stats for number & types of attack and which shield is most popular which would be updated every hour. That would allow the balance to shift more frequently as people adapt to increased usage of a certain shield. Less frequent updating of the stats would give time for the meta to shift so even if it was updated every day that would be very interesting to see how players adapt to the changes. There's any number of ways to improve the experience by improving the feedback players get for their shields, similarly to how it's done with hits.
This would apply for snowball fight as well
