Said new author would also explore areas that Lynn would rather not have revisited. Areas like the house to the left and the family therein. As we know, Anne vanished from the strip owing to Lynn's shrieking refusal to think about her first divorce and Lynn is cool with that not wanting to see what really happened. New blood wouldn't have that hang-up any more than they'd have a problem killing off Jim. It's no skin off their nose if Merv never gave Lynn the answer she wanted when she asked "Shouldn't you have forced Mom to treat me better?" so they wouldn't have seen the need to keep the man's avatar alive to punish the contents of an urn for 'failure'.
Worse still, the new person would have kept the strip going after when Lynn thought the story was 'supposed' to end. This means that we'd currently be talking about April's love interests and the first years of Liz's marriage because (as I said) they wouldn't have come to the conclusion that just because Liz said her I dos, that meant the story of the Pattersons was over.