The "fact" that pretty much all the iOS releases until this one looked about the same might mean that this one might be different since it's quite different than all the previous releases. Couldn't it?The fact that there's a pattern means they usually try to stick to a schedule.
The actual fact is, again, that no one really knows, and guessing, based on previous patterns or not, won't really change anything or really provide any useful information--beta updates will come out when they come out.