I generally think it's ridiculous to bring popular actors back to different roles (I am not even going to touch RH or ME because I am not sure their characters were popular to begin with). Claudia/Kim weren't even twins or doppelgängers. The audience was just supposed to pretend we didn't notice and that's just disrespectful.
Claudia had potential, but she got some awful, misogynistic writing and I believe it was Sarah's choice to leave.
And Oscar's mom was set up to be such a mystery and it turned out to be Kim? A woman we didn't know or care about lol. And the show didn't even try to re-pair her and MB. So weird.
I had forgotten how much I liked SK's AJ and LW's Carly. I even liked him and Liz. What a shame......