Time to get creative.
Pick an unplayable champion. Design a very specific set of nodes that will make that champion great, if not insane or OP. Oh and try to not be too obvious.

A good example would be Guillotine (constant regen from any damage dealt to defender) and the mystic nodes from last December. Just corner the opponent, heavy spam, heal constantly, power drain constantly, win the fight.

Cheers 🍻