BH isn't really a great carry and definitely isn't a hard carry. Mediocre farm ability mean he's entirely dependent on ganks and his ult for money, which requires that his team have good teamwork and more or less constant ganking. Mediocre hp gain and the imperative to go straight damage items mean to maximize his potential you'll be squishy more or less the whole game. While he can pump awesome 'crits' with jinada, jinada will always have at least 6 seconds of cd, whereas a hero with buriza can get many crits in that same period.
To boot, he's a 'stealth' hero. An integral part of his hero is windwalk, which doesn't help at all late game, particularly if he's pumping damage, because most teams facing potent invis heroes will buy a gem and throw it on their tank. Since his hp is meh, unless you specifically build to fix it, if you see bh coming, he's boned.
That said, his track has the potential to earn his team a whole lot of money. A maximum of 850 extra gold for each hero killed while tracked is enormous and the ms % is huge (that's a 4250 if it's a 5v5 and his team wins with no hero losses!) . Shuriken ministuns and, while he can't out-carry many actual carries, his burst is quite high, especially once he gets desolator and medallion, which makes him perfect for killing squishy nukers and isolated farmers. He's an enormous asset to his team.
IMO, he's much better played as semi-carry/support, with the team having a more conventional carry to rely on. If he gets a rocky start, he'll have an incredibly hard time getting the items he needs to carry and that's what makes him so much inferior to the more popular carries like lycan and am, who's ease of farm will let them get their key items by 20 minutes, essentially no matter what the enemy team does
I'm pretty sure the reason why we aren't seeing void in pro matches is because he requires quite a bit of farm to do well (he does need more than MoM
). While games are starting to last longer, push strategies are still prominent and effective. If he wasn't picked because his ult was easy to counter and avoid, we wouldn't see enigma get picked either and we see enigma in every other game.
PL's pretty weak, since he has such big mana issues and needs quite a bit of farm. If you can find the real one (pretty easy if you've got aoe), he's quite easy to kill until he gets some big tank items.
I'm actually interested to see if KOTL can stop early pushes altogether. If wave can slow down chen and enchantress pushes, we might see kotl in dota 2 pro play! Also looking forward to medusa and the few other people will spells that pierce magic immunity.