The Queen Vic will be rebuilt so not really a reason to leave. What about her precious FAIRMILLEEEE. Surely they would be a reason to stay. After all shes the one who always talked about how precious FAIRMILEE is.
IMHO the poor reason for Peggy leaving is that the luvvies at the BBC want to keep the door open for her possible return which doubtless she will when the work dries up.
Have to disagree with you about her being Queen of the Vic. For me it will always be Angie.