Hi,
Unfortunately this isn't feasible for a variety of reasons -- mostly due to the rapid release cycle cPanel employs (we actually don't update as often and frequent as many other providers unless we deem it necessary (IE: important bug fix, security update). This also affects posting notices -- there would be *a lot* of updates posted constantly and the vast majority of them aren't service impacting minus cPanel being unreachable for 5-20 minutes. In the case of today it was the latter - a cPanel TSR which will be disclosed in a few days so updating ASAP is necessary (especially when you have a large fleet of servers).
Lastly non-peak times is subjective depending on who you're asking -- we have a very large international customer base. Depending on the spread of users on the servers what may be peak time during the day for you could be 1AM elsewhere. We can't make the assumption that every maintenance window will be affecting North America based customers.
Unfortunately until we can find a graceful way to resolve these issues we'll continue pushing updates as we have for many years.