Do you not pay attention? It says in the change log that it has been fixed in 14w33a.
Could not replicate. Need more information. What did you do that informed you that they are switched?
This bug is most noticeable at night for some reason.
Yeah, I should have put more information in. It renders invisible at certain angles. It's since been fixed though, just confirm the bug as fixed.
Yes, there are supposed to be gaps in leave blocks when graphics is set to "fancy". If you want to reduce some lag, you can set this display to fast and your leaves will look like how they used to be and maybe you game will be a bit faster too.
Go to options, video settings and then click graphics to change it to fast.