Moira was another one on the chopping block, with the Undertaking plot over, her character really has nothing to do except be a normal mother now. Presumably she'll be reduced to a recurring role next season, or maybe just one or two appearances in the whole season.
I hope not, they have to keep her, Susannah Thompson is too good to let go. They'll find something for her to do, she's not a normal mother, she's Moira Queen and now probably hated by most of the city, she has to redeem herself somehow.
The current main character they should get rid off is Laurel, she's this show's Lana and they found their Chloe with Felicity, they should dump the dead weight.