My first love was the Rapier, and I still use it in legendary.
It really all depends on your play style, but it’s excellent for headshots and I like it with both Zealot and WHC. The Alt-Fire is also great for staggering enemies and keeping at range. You can stagger faster if you fire it, then double swap weapons, and fire again. This effectively doubles the firing speed. And while most standard chaos dudes take a couple sword swings, the alt fire will OKO them at close range.
For Leg rolls on the weapon, I like Speed or %damage on block for Zealot, and Speed or better yet 2% recharge on crits. You can recharge most of your F before it’s finished with AS and spamming it. Also note that the Rapier only takes a HALF shield to shove with, so it might be worth taking the 50% increased shove strength on attacking enemies to really knock em back. Not to mention WHC getting all free blocks to light attacks, or Zealot getting like 8 shields on low life, which just means 16 shove attacks at super fast speed.
I love using both careers and I’ve come to kinda not enjoy BH. It’s too easy to just destroy things.
The Flail is great if you can time his Charge attack and use attack speed. The charge attack is Shield bypass as well. I’ve only tried the axe a couple times but holy moly does it do damage to specials. Just terrible at wave clear so your main job becomes specials. Have to have a team willing to clear trash so you can concentrate.