Thunderlords and Ranged vs. Melee champs
In my opinion of game balance thunderlords should not be able to proc from auto attacks.
Edit 1: Thunderlords shouldnt be a one size fits all kind of shoe it should synergize well with the champions role, kit and flaws. For example dfire synergizes with brand cass and fizz, olaf and shyvanna and udyr do alot of damage but have trouble sticking to their target so stormraiders surge would be good on them, talon has a bleed and alot of burst and has trouble keeping up or escaping after he does a full spell rotation so you could go stormraiders thunderlords or dfire. Leblanc does alot of burst damage has no troube with escapes and does not synergize with deathfire so thunderlords would be good on her.