I think Blade Dance is annoying af, true, but DH’s are squishy af.
If they had no blade dance immunity they would get demolished by every spec hands down.
As MM, Havoc is relatively easy to kite and even easier to bait the blade dance because they know all of our shots hurt like a MF. Blur is another annoying CD but countered by Freezing trap. Binding Shot into a double tap followed by Sniper Shot always makes a DH defecate bricks and forces them to either use BD, Blur or both if you bait right (maybe even darkness).
Best advice I can give is wait for their BD to be used and then use your damaging or utility spells. Get ability tracking addons.
You can tell as a DH when a priest is going to fear or a monk is going to stun for example because they have obvious tells, you simply have to bait the same way caster’s bate interrupts.