The only time I saw Surge used effectively on a champion was a Kog'maw who didn't want a second escape summoner. If you think about it, Surge is the only offensive summoner that makes sense on him, much like how exhaust makes far more sense on Karthus than Ignite. It's still an extremely questionable call over cleanse or heal, but since he wrecked with it, hey. I've heard of it being used on Kayle, Jax, Skarner, etc, but for virtually any champion that'll be in close range ignite is usually better. Kog'maw was the only real exception to this due to range.