I think the Ender Dragon fight is getting there. Right now though I think it's too easy to melee smack her when she hovers on the portal, as she only fires in one direction and won't turn around to fire in your direction and you could just avoid the acid pool by smacking her feet. It should require some maneuvering to melee her when in that state, not walk around her and spam m1. Hopefully that'll get resolved though.
Then there's still the problem of the dragon fireballs not actually firing sometimes despite hearing the sound.
It should be that the more crystals you destroy the more she aggros you (like it's actually NOTICEABLE).
When you've destroyed all crystals she will have a higher chance to charge at you and lesser chance to sit at portal.
That's more or less how it is right now. She switches to her strafing behavior (i.e get close and shoot fireball) everytime you destroy an ender crystal and she prefers that behavior after all of them are destroyed.
Shield damage blocking is also directional. Shields will only block damage if it is coming from (roughly) in front of the player. Projectile damage is completely blocked while melee damage is reduced to one hit point. Neither fire damage nor explosion damage is blocked, although the initial damage from blaze and ghast fireballs is negated.
Interestingly, shulker bullets are counted as melee. Also, tipped arrows still apply their effect regardless. This makes damage arrows (or health arrows, for that matter) especially effective against players with shields.