I found blazes spawn far more frequently from blaze spawners, almost in a constant stream from blaze spawners in 14w28b. Literally one wave of blazes spawns almost every second. Even with torches on the blaze spawner they still spawn about every 3-4 seconds, it's like they made no difference. Which is weird, as another blaze spawner is actually very close to the one I was at, and it wasn't spawning any blazes. Yet that one had 5 torches on it before I entered the nether in my current world. Bug?