30 seasons is fine. An hour-long episode to top it off and get 670 episodes. Then done. They'll be at roughly a 2:1 ratio for overall Simpsons quality, 2 bad episodes for each one from the Golden age.
Yas! A bit awks to end on 669 episodes. Maybe have a mega season if 30 is really the end. Watched every episode and will continue until the end!! Also Julie Kavner's voice has been sounding off recently. Guess that can't be helped, but I miss Marge's '90s voice.
Legendary. 
i still love it