I prefer manual weeks.
I see your point, but I believe I only created several automatic weeks like the usual:
4th of July
Past ATW themes
Celebrating Death Week
Opening week for each major sports
But the rest of the weeks are manual weeks, where anybody can run it. Unless and I cant guarantee it, that user wants to dedicate that week to a holiday and sports theme?
So out of 52 weeks, there only maybe a dozen weeks taken to automatic themes and we have nearly 40 weeks where users can create manual themes.