GP Barrels and the gold reward they grant to an enemy
Personally, I feel like GP's barrels should not reward 10 gold, but rather a value of 5 or so.
If you look at Heimerdinger's turrets, if I remember correctly they grant 12 gold on destruction. Zyra's plants reward 5 gold,if I am not mistaken, and the same for Shaco's boxes.
Meanwhile, GP's new barrels reward 10 GP, and require 1 auto attack to destroy. You can also spam them out much faster than any other "turret" champion. I personally feel like this is extremely silly, considering if you are against a ranged champion, they can attack it faster than you can parrrley.