I think OG Brann should now be core thanks to King of the Underbelly.

You have the option to OTK with double Brann + Parrot → 4 King Crushes = 32 damage.
Against Renathal mirrors, you can keep the weapon equipped before the OTK if necessary, adding the 8 missing damage.
This only works with an empty board, but if your opponent doesn’t clear your board, you win anyway.
You can also tempo out half of the combo with double Brann or Brann + Parrot, for only 4 board spaces and 16 damage (+ your board).

This version is a lot more consistent and tempo-oriented. It plays fewer bricks and is less greedy than the Leoroxx OTK version. I think this approach should be the optimal one, and I say that as someone who preferred the Leoroxx version until last expansion.

Here, the OTK is just an option. The main gameplan is to play for tempo. You can usually out-control aggro decks, disrupt and kill combo decks quickly, and either OTK or out-tempo slower decks/piles.

 

Those 3 ETC spots are now mandatory. Serpent bloom is core of course.
Platebreaker is very useful for turning the OTK into a guaranteed kill button in some matchups. You can’t afford to add it in the ETC of the Leoroxx version, since you need both Serpentbloom and Rhino there.
Flare is also mandatory because Smothering Starfish (for mage match-up) has been cut for a more consistent Beast package. This is especially important in this version to consistently access King of the Underbelly.

 

For King of the Underbelly, I tried every imaginable card (yes, even 8 hands from beyond). I think your three cards should be :
Spirit of the Badlands, an alternative to Naielle in your gameplan, just be careful of Theotar vs Piles (keep a huge hand)
Parrot, for the OTK or to double some of your disruption tools.
Felrattler, an additional board-clear option with Serpentbloom.

The main flex slots are some of the 1-drops, especially Trogg, and also Clumsy Steward.
You can also potentially fit Customs Enforcer, Mixologist, Titanforged Traps, or Reno Lone Ranger somewhere depending on your expected matchups.
Sometimes you don’t find Naielle/King of the Underbelly or their respective tutors in longer games, and you lose.
Otherwise, the deck has a very flat matchup chart, but it has tools to win against pretty much anything, as long as you have sufficient knowledge of the Matchups.
I feel like the deck has more favorable matchups than before, mainly because the curve has been lowered significantly so it doesn’t struggle vs hyper fast aggro anymore and still has reach in the end game.

No stats because I played on mobile.
The deck can probably go a lot higher if you have the time to grind.

Don’t hesitate to reach me on Twitter if you want to discuss about deckbuilding Highlander Hunter : @DreadlashHS

I hope you have fun as well with the deck !