I'm sorry to hear about the news of The Ghost and Molly McGee, it's always sad when your favorite show has to end.
Two of my favorite shows (Futurama and Metalocalypse) ended in the early 2010's, so I know how you feel.
In my opinion, I think it's better to end a series once ideas start running low, otherwise it becomes boring and tasteless as more seasons keep being reproduced. I'm not sure if that was the case for TGaMM, though.