The ender dragon used to occasionally dive down to melee attack the player. Now it doesn't seem to do that anymore. This makes the boss fight a lot easier (even a bit boring, especially when you run out of arrows), as the only thing you have to look out for is the dragon's breath.

Based on my tests, this bug has existed ever since the dragon fight was revamped in 1.9. It did hit me a couple of times in the 1.9 test, but that might have just been coincidence. In 20w12a (and later) it didn't hit me even once, except when it took off from the nest. A clear difference when compared to 1.8 and earlier, where the dragon would align itself towards the player and then start diving.

I've also paid attention to this in gameplay videos on the internet, and I haven't seen the dragon dive in any of them.

To clarify: I am not talking about the dragon swooping down to land on its nest, which works correctly. In the Wiki (which of course isn't perfect) this is referred to as the diving state.