As far as I can tell, this has been fixed as of version 14w03b.
Oh dear. Thanks.
Why was this marked "works as intended"? Does anyone have any reason to believe this is not a bug? By the way, I tested this in 14w02c, and furnaces still don't give XP when mined.
I have this issue, and I use JDK 1.7. Whenever I'm near a horse I get lag spikes, and riding a horse is very stuttery.
It may be of interest to note that stairs can still be placed upside-down. However, they will only face one compass direction as well.