Blitzcrank's Sugarrush
Reworking a cool ability because players don't like to play against it is a flawed approach to doing reworks. If the ability is balanced, then it gives a rewarding feeling when used and it's okay to strike fear into the hearts of your enemies.
An example of bad balancing is thinking that you need to create crippling weaknesses to balance an ability. For example, Blitzcrank had his W changed so that it debuffs him with a slow. This sort of mechanic gives a bad feeling whenever using the ability.
These are psychological interactions and shouldn't be overlooked. For example, I've recently been reviewing champions and trying to decide what I want to play in Season 6. I know Blitzcrank has a good win rate and his grab is cool. But I don't just want to win next Season... I want to have fun while doing so and the slow on Blitzcrank's W is actually a serious consideration in whether I will play Blitzcrank often in the next season - not because I think it affects his playability or winability but because it affects his funability. A more healthy balancing effect would be to reduce Blitzcrank's base movespeed or to couple the slow effect with increased range on his pull because it balances the psychological funability of using his W.
Naturally, this is my own personal take on funability, but maybe there are players out there who disagree...