Garen, Q-W-E-run or Shen E-Q-W are both pretty easy champions to master that dont really have too much neccesary variation in playstyle. Yorick is another person although he isnt exactly 'fun' to play, but he even more certainly isnt fun to play AGAINST.
BRAUM IS A BRAINLESS CHAMPION WELL HE IS A SUPPORT THAT'S THAT GOOD BUT.....BUT!
he is a pretty stupid champion looking at his skills e-w or w-e to defend ally then q to slow then stun is actually not bad but r what da hecks wrong with! rumbles equalizer is better he just knocks them up into the air then walla! yasuo ult! what no yasuo! then **** dat ult useless no damage when mo yasuo!pfttttftft=>
Braum is far from Brainless. He requires very good reaction timing if you're to play defensively if your ADC needs peel. A good Braum will try bait spells by looking like an easy target and at last second use his shield. He is simple mechanically but he is harder than Leona imo due to his varied playstyles.
Anivia's got a bit of a learning curve but is extremely mindless once you get used to her. Same combo in nearly every situation, very easy mechanics, and she's still relevant even if she gets a little behind with all of her utility.
Both come up to Caitlyn either way.
Other braindead champ i can think of : Garen, Darius, Ryze, Tryndamere, Warwick.
he is a pretty stupid champion looking at his skills e-w or w-e to defend ally then q to slow then stun is actually not bad but r what da hecks wrong with! rumbles equalizer is better he just knocks them up into the air then walla! yasuo ult! what no yasuo! then **** dat ult useless no damage when mo yasuo!pfttttftft=>