You stagger changes like this out slowly for a day or two and listen for the screams. You make the download available early for those who want to take the risk of adopting it on the first day, because they are the type of experienced and obsessive-compulsive people who can identify the causes of problems and are likely to report them.
This is PRECISELY how it should be done.
Agreed, except that AFAIK Google only released an update that could be installed if the user was rooted. When you do that, you only get report of issues from people who are rooted, and obviously those users could have other factors influencing the performance of the device. IMO they should have released an update that could be installed w/o root for the early adopters who haven't rooted and don't want to do so.