Lion + Skywrath Mage

Why this works

Seeing Lion and Skywrath Mage on the same team often leads players to expect easy kills. The theory is that Lion's long stuns and Hex provide perfect setup for a full Mystic Flare. In practice, both heroes are trying to do the same job: delete a single target with a full spell rotation. This leads to a lot of redundancy. When both heroes use their full kits on one enemy, you’re often spending two sets of major cooldowns to get a kill one of them could have secured alone. This can leave your team with very little to offer for the next minute or so.

As the game progresses, this single-minded focus becomes a bigger issue. The enemy team knows exactly what to expect and can itemize accordingly. A Glimmer Cape, a Pipe of Insight, or an early Black King Bar on a core can shut down your team's entire game plan, since both Lion and Skywrath Mage offer the same kind of magical threat. Your lineup also ends up lacking the versatility another support might provide, such as a save, a dispel, or the ability to push waves. It puts a lot of pressure on finding isolated pick-offs, because broader teamfights can be very difficult.