I like the release schedule but I agree that bugs are an issue and that the team is struggling to catch up. I'm not sure anything could be done about it though. They broke open stairs in November last year and it's been six months now and they haven't been fixed.
So I'm not sure a slower release schedule is going to improve much except that we will maybe see less bugs for new packs. I think that's part of a larger issue they have though when it comes to quality assurance and bug fixing and we who are playing their game have not seen much improvement there except the laundry list and sims 411.
I'm hoping that Maxis opening new studios could help in this area because whatever people they have working on this right now is not enough.