Proceed at your own risk. Kaladin's arc is based around how everyone close to him dies, he must take the death of someone extremely close to him and accept it. There is no one closer than Syl. This is compounded by his admition that he needs to be there for the living not the dead, so unfortunately Syl must die irreversibly and totally, sent to the Beyond dead. I can't see a way around it and that terrifies me, but I see nobody else close enough to Kal to maximize the feels.