His ai is wonky and needs to be fixed otherwise he'll be a liability and can result in match losses.
* Instead of pulling an enemy at the start, he runs towards the closest enemy and then pulls the enemy furthest away (instead of right at the start of the match).
* When he does pull someone, he sometimes does not knock them up and instead runs towards the enemy that was closest to him (before pulling the initial enemy) after which he walks back to the enemy he initially pulled to knock it up and fight them.
* When he does pull someone and knocks them up, he sometimes wanders off to the next closest enemy and sticks to that enemy (completely ignoring the enemy he initially pulled and knocked up) until they die.
* When he does pull someone, he just wanders off to the enemy that was closest to him (before he pulled the initial enemy) and sticks to the new enemy (using his knockup on the new target etcetera).
* When he does pull someone, he just wanders off to the enemy that was closest to him (before he pulled the initial enemy), knocks that enemy up and goes *insert genius meme here* while running back to the enemy he initially pulled.
1. All of these things occurred while there were empty hexagons around Blitzcrank.
2. This behaviour happened both with a Rapid Fire cannon and without a Rapid Fire Cannon.
3. There were no assassins on my team at any point while using Blitzcrank.
4: There was always atleast 1 empty hexagon in front/to the side of Blitzcrank at the start of a match
Just have your QA team set up a match including Blitzcrank (any * rank is fine) and let that match play several times and you'll see for yourself that the ai is wonky.
For those wondering about the genius meme:
https://i.imgflip.com/3kzvi.jpg <- this is it.
That is how I picture Blitzcrank's thought process when any of the above mentioned points happens.