I don't get Talzin under EP lead. Her main use if the plague mechanic - which prevents cleanse - and EP wants his enemies to cleanse themselves, feeding TM to your team.
Also, Talzin is pretty squishy, and part of the reason Nightsisters work is because they revive one another. Without that, Talzin wouldn't last long. And get healing mechanics also work only on Nightsisters, and wouldn't benefit the rest of the team.
So... No, I wouldn't make the switch. Both EP and Talzin are great toons to have, but not together.