Anti-Mage + Sniper

Why this works

Having two cores that both need a lot of farm can stretch a team's resources very thin. Anti-Mage wants to split the map and find isolated farm, while Sniper wants to do the same from a safe spot, usually near his team. Neither hero provides the lockdown or frontline presence the other needs to be effective early. Anti-Mage can't really protect Sniper from getting jumped, and Sniper's slows aren't enough to set up Blink-in kills for his partner. They both need items before they can fight, and they don't do much to help each other get those items faster.

This often leads to a mid game where your team is forced to give up map control and avoid fights. The enemy can group up and take objectives while Anti-Mage and Sniper are still farming. If your other three heroes can successfully create space and stall the game long enough, having two powerful late-game carries can eventually win you the game. The risk is that the enemy team will simply run you over before that happens, punishing the greedy draft before it gets a chance to come online.