Speaking of Chapter Keyword - Another tidbit is that apparently bonii from an Ultramarine Commander (ie the rr1's aura) doesn't affect models with the (for example) Imperial Fists Keyword, though apparently you CAN choose to make every unit in your army have a different chapter/legion/klan/hive fleet/craftworld/regiment/[whatever] should you so choose. Hopefully this is true as I always felt that while you could reasonably expect an Imperial Fist and a Raven Guard to work together if required, they certainly wouldn't be well enough versed in each others tactical subtleties to make use of their specific rites and chapter specific way of warfare, much like how it didn't make sense to have Azrael always kicking around with his 50 guard besties instead of terminators/honour guard from the DA elite.
That is the most reasonable changes in the entire edition. If those Aura bonues can be made selective though keywords then they do have the option to make them much more interesting as well.