Permanently:
Zainab Masood - There is so much going on with the Masoods at the moment and it's crying out for her. Nina Wadia is one of my favourite actresses. Hope DTC reaches out to her.
Sam Mitchell - Kim Medcalf of course. She still has plenty of family on the Square and there has been a long enough gap to get over the crap of 2009. I can live with her being a mother to Jack Branning's son. Just get her back. Maybe if Aunt Babe (I think?) sells her share of the Vic, Sam could be the mystery buyer. Shock Phil of course.
Vicki Fowler and Spencer Moon - A recast for Spencer as Chris Parker is no longer acting. I'd be willing to give Scarlett Alice Johnson a second chance if she's interested. Martin's back on the Square and has a child on the way. Vicki's his niece and Spencer was a good mate who's still with her. I don't know what Alfie's future is, but it couldn't harm having Spencer back. Oh and Sharon is Vicki's adoptive sister so there's definite family connections still lurking around.
Temporarily:
Glenda Mitchell - She should've been brought back these last few months. Glynis Barber is fantastic.
Zoe Slater - If Michelle Ryan isn't willing to return full time they should try to persuade her to come back for a one-off stint. A useful character to have around if Kat's mystery son is revealed.