to expand on jlgreco's point, not only are you now allowed to get off in the back it is strongly encouraged. Advertisements as well as signs on the bus itself tell you to get off in the back, and in my experience everyone does. Even though it's only been a couple months, bus rides are noticeably faster.

You are correct about rush hour busses out of downtown being absolutely packed though. While it can be an unpleasant ride, passengers are very rarely turned away.