Not sure why there’s any debate about Parthans. They are, to date, the best in slot bracer for WW.
Could Mortick’s take over for the Crimson variant? It’s possible, but I’m not convinced–and won’t be until I see some clears with them.
Parthans do not cap. They provide more mitigation than any item in the game, including Band of Might. Yes, they take some careful monitoring, and yes, they require you to manage your CC applications, but they’ve been the go-to bracer for a reason.
They do not provide “20% on average.” I don’t know where you got that nonsense, much like the nonsense about “useless vs RGs.” This is WW we’re talking about, and and it’s always going to require fishing, including for RGs.