Dark Ranger, Beastmaster and Naga are all picked by various races for various strategies and support tier one heroes fantastically. Mana Drain and Banish are extremely powerful in the human army that is about persistent fighting to wear down opponents. Mountain King is really strong for example and can be a single hero to power to 6 for Avatar but generally works best with an Archmage or a Bloodmage backing them up. Tier 2 is for heroes that can be picked almost any time, make decent first pick heroes but shine better with additional support or can't carry the game themselves but greatly assist another hero or a specific strategy. First, second or third position and it'll do fine. Pandaran Brewmaster can be picked by any race, any time. Also, the blademaster is a terrible second or third hero due to it's fragile nature, lack of strong support from other heroes beyond the Shadow Hunter and needs items to really be powerful. Orc players practically have to pick Blademaster because their army isn't very damage intensive but thats a discussion for a different time. The only reason I wouldn'y put Blademaster in it's own tier is because the orc racial bonuses aren't that potent.
Death Knight can heal and provides Sanic speed, Archmage has a useful summon and the best aura, Demon Hunter has Mana Burn. No doubt Blademaster is God but Death Knight, Archmage and Demon Hunter can fit in to any strategy by their respective races and can be picked at any stage of the game and be useful. Well, if we include the racial bonuses and strategies then the tier list is different than just a list of the heroes in a vacuum, here would be mine assuming racial bonuses and the possibility of dual-heroing or tri-heroing: