why don't you guys chill out and just wait 10 days. If they announced the changes now it would just lead to a barrage of "OMG CHANGES ARE SO OP" posts, even thoug no one has even tried the changes yet. it wouldn't really add much value to the community to receive this information early unless they were announcing something like major new features.
You're right, but let's take a look at other ways to announce a patch,get people hyped AND keep everyone calm.
One particular example, is Riot Games (LoL). As I remember from a couple of years ago, they release a video prior to the patch, containing some basic information, just for the players to "understand the thought process" of the changes. Instead of just putting the patch list on the forum.
As you said, posting the exact patch note before the actual patch is not good, considering people expect too much from the patch at this point and are expecting a miracle from the Balance Fairy. But they can just mention a few things they have in mind.
For example they can say: "OK, we are aware that the blobbing is an issue-specially when playing against OKW-So expect some changes in the suppression mechanics". OR, "There will be some changes regarding late game, since Allies players, specially USF players are struggling against Super Heavies.
This way, people kinda know what to expect, they get some of their anger out of their system before the actual patch, and -in rare cases!- there might be some constructive feedback for the balance team.
Anyways, I prefer not to know anything before the patch, instead of a shitstorm 10 days before the actual release.