I'm just hoping the Game Mechanics team sticks to a clear plan and doesn't make frivolous and untested changes.
When revising the Star Wars RPG, they apparently just decided arbitrarily that you shouldn't be able to fight defensively when making a standard attack anymore. You could use total defense as a standard action, and could still fight defensively when doing a full attack, but not during a standard attack.
We never did get an answer for why they made that change, except that it was intentional, not an editing error. Some conjectured that it was to make Combat Expertise more valuable as a feat, but then why only eliminate it for a standard attack?
I am fairly certain that they weren't responding to player feedback when they made that change, since I did a search of the boards and didn't find a single person complaining about how you shouldn't be able to fight defensively during a standard attack action.
I got the feeling they were just stuck that in after a conversation at lunch, because it seemed like a good idea at the time, but never talked to anyone else about it, much less playtest it.
Here's my cool thread on the topic:
http://boards.wizards.com/rpg/ultimatebb.php?ubb=get_topic;f=180;t=001550;p=