I agree with most of your post, but it looks to me more like they changed the rules to *allow* hordes, not to encourage it. You do lose your ccw, and a lot of cool rules if you just run naked Bolter/Pistol Marines.
The thing I think is awesome is that it *appears* to be following suit that there is no perfect right way to build your army. That is a more fun option.
Also, undefeated depends a lot on where you are and everything. My meta is a lot less vehicle heavy, and I ran a Tyranid List that went undefeated except for a time when someone was fudging the rules (we kept playing because we were having a blast, I just took pictures to remind him forever on facebook!)