Rumble's CC

Though it's easy enough to get ahead of an enemy who forgets to buy MR or when you have a jungler who helps a LOT, it's just too little to think Rumble can stand up to the other fighters. Main problem being they can simply walk out of his ultimate during a duel. It's not wide enough to keep them inside it even when they're autoattacking you, and the very small slows don't do much to keep them in since the harpoon doesn't stack on top of the ult's own slow. (correct me if I'm wrong)

I think he should have more than just a non-piercing skillshot slow. Jax, Renekton, Riven, Nasus (more reliable, targeted slow), Yasuo, Shen and plenty more fighters have much more reliable CC in the form of stuns, Knockups, and taunts, since as solo lane champs they don't have a support to do such things for them. Rumble, however, whose main damage requires the enemy to stand close in front of you and on top of a set rectangle, has only his slow. Just as well, the harpoons do little damage, despite the fact that they can be blocked by minions and are thus harder to land than a pierce.

In my opinion, it would be an OK fix to make the second harpoon root for a short duration. Nothing else, just a short root on his second harpoon. Thoughts?