This is from Buffy.nu:
Did Whedon End Buffy? Will He Cancel Angel?
All fans believes that Buffy ended because of Smg`s decision. But now, new information has come out...and Whedon perhaps may also end Angel.
Whedon seems to achieved that to some degree and is relieved that, thanks to renewal, no one will show up to the set of Angel and say "stop filming that now," but one day that phrase may well be spoken, and possibly by Whedon himself.
"It could happen," said Whedon. "I did that on Buffy. I was definitely done after seven years. A lot of people attribute that to [sarah Michelle Gellar], but after seven years I was burnt out. I was just really worn down as we came into the seventh season. Of course we tried hard to make it great, but seven years is a long time and I was tired. Now were in the fifth year of Angel and I’m in a situation where we’ve gotten to the hundredth episode and I feel like the show has...found it’s place in the world."
Pretty interesting actually. I can see why Joss would want to stop Buffy because there really wasn't anymore for the characters to go.
On the other hand, Angel still has plenty of steam in my opinion. I am asking for one more season, then Joss can take a break after that. I am sure he is catching up on sleep since he doesn't have to do Buffy or Firefly anymore.