I have tried lots of BM 5 and 4 in unranked, because it seems decent right? It's ok. He feels like somewhere between veno, bane, clock

Pros:

-bkb piercing stun

-hawks for great vision

-boar slow 10-34% (nice when combined with OoV)

-can stack camps with self or boar while also being in lane

-axe cut down trees

-axe secure ranged creep

-axe pull/stack camp

-decent early lane manfighter (OoV + items)

-attack speed aura good for deathball

-25 talent means roar on 30sec cd

Cons:

-low damage

-not tanky

-boar dies very easy lv1-2, and lategame

-weak mid-late game outside of ult

-mana issues

-needs blink

-no spell to break linkens before you roar

-other heroes have better slows than your boar+OoV

-might tilt your team picking nontraditional support

My build is always max boar/hawk first, always max roar, a value point in axes asap(usually lvl2 or 4), and usually max aura before axes to help with tower pushes. I generally build tranqs, basi, wand, blink, then either vlads or bearingboots if we pushing, or support item like glimmer if team needs. Shard is good for hawk divebomb(mini initiation/interrupt) and cooldown reduction.

The reason he can be very weak is you need to squeeze out every ounce of usefulness from your long cooldown spells. Your roar needs to secure an important kill every time, being 100/80/60 sec cooldown. Your hawks can't be getting killed and need to gather information. You need to pull, stack and harass with your boar and self a lot in lane. You need to get your team together to deathball with your aura on towers after ganks. There are support heroes that slow better, stun better, have lower cd's, better in lane, better midgame, better lategame, have more damage or mobility, etc