the thing with blitz is that he auto pulls whatever he grabs to himself. most blitzes will grab the squishies, which is correct. However if he accidentally grabs a tank or someone you really dont want in the middle of your team (example: amumu, karthus, shen) then he can really screw over your own team. the rest of his kit gives him mobility and some burstiness. at the same time though, remember that you should be giving the kill gold to your marksman whenever you can, which brings another point that blitz's ult passive can deny your carry creep score.
nautilus is a disruptive tank, he will try to land his Q onto someone and get HIMSELF closer to them as opposed to the blitz Q and thresh Q. He will rty to crowd control them all with his on-hit stun and his aoe slow while shielding himself and giving himelf bonus damage. he has good dueling potential a well with atk speed items and tankiness. He's generally very annoying to have in your face.
now thresh, his Q, if i remember right, supresses the target for a bit and here's what makes him a little different, he can CHOOSE to follow up on whoever he hooked or not, meaning if he hooked a tank, he can ignore it and let him go, if he hooked a priority target, he can go in and apply crowd control to keep them there for a good while with his box and flay, both of which can also be used to disengage an enemy and his lantern that can save your carry by allowing them to displace themselves towards thresh's position, something blitz nor nautilus have. Hishook and ult can really mess up an enemy team and put them in a bad position with that massive slow.
