The Amunet character is intentionally played as over the top. No one (including Katee Sackhoff), takes her seriously as having any depth. Almost 'It's so bad it's good'. Iris is just a poorly written and acted character.She's not the worst. Amunet is worse. nice characters are always less desirable. Remember how bad ass zoom and Reverse flash were?
Oh and for ladies of Battlestar, Kate Sackhoff is certainly looking her age, but Tricia Helfer is still absolutely stunning (both on Lucifer and IRL when lucky enough to meet and get a photo with at a Convention a couple of years ago).