I used to only play team because I couldn't figure out how to answer the blademaster in solo play. Until I figured out the bloodmage. I don't think team is a good indicator of game balance. Aura and Area of Effect heroes become the best choices.
For Orcs, I would say solo Tauren Chieftain with shockwave and aura is your best choice. For Night Elf it's KOTG (with entangle and aura) and Priestess (with owl and trueshot). For Human it's Archmage (Blizzard and Brilliance Aura) + Pit Lord + Blood mage (with lamestrike). And for UD... well, they're the weakest in solo, but they own teams with their nuking and speedheal aura.
Blademaster gets weaker the more units there are on the field. So in team play, he's gonna be weaker.