Joe Paterno is a legend, and he earned the right to go when he wants to. However, since 1999 their yearly records, in order, are...
5-7, 5-6, 9-4, 3-9, 4-7, 11-1, 9-4
So there was three good years, and four god-awful years. I think it would be best for their program if he stepped aside and turned over the reigns to some young coach. However, I also think Paterno thinks he will probably die soon after retiring (a lot of people who have worked one job so long would), so he is holding on for as long as he can.
* Side note: That 3-9 team was won of the powerhouse teams Solich beat to achieve 10-3. The other two ooc teams that year were from the Sun Belt Conference or whatever it's called.