I used to main DH back in legion/BfA, and I really liked the class. I just discovered that needed to play my char again for certain activities (cough Siren Island related stuff cough).
After playing for a couple hours, I absolutely hate the Havok spec. There’s no “spammable” button like frost bolt and such like. I’m forced to auto or use Felblade to build fury or be starved of it. I’m so disappointed and I really don’t want to play this class anymore.
Then don’t? Why would you need to play this class for Siren Island?
What level are you and what is your gear? With current set bonuses and vengeful retreat, sigil of flame, immo aura + felblade you have alot of fury and able to spam skills. Actually, I dont ever run out of fury and dont even need to use my fury generation skills all the time, just use them wisely.
Havoc DH is in my opinion much more fun than mage 
Demonhunters need a lot of love at the moment. Only having one viable hero talent tree is just the tip of the iceberg. We’re a very big iceberg.