Just pasting my response from the league board.

Yep, this would be an enormous nerf to champ that is already okay. In order to compensate for the increased cooldown on Q at range and the removal of his guaranteed stun he would need to have his Q be spamable in melee and at a reduced mana cost. Basically, if he is within melee his Q needs be at something like a 2 second CD.

The changes you propose means he auto loses lane to any strong melee that has a dash. Think Riven, Renekton or even Talon. All of them want to be in melee and All of them can choose to enter melee basically at will. So, now you have this version of Pantheon that is useless in melee if he hasn't primed these conditions. The "aspect of war" would just get his ass handed to him by a crocodile or a moody kid with daggers. Additionally, no one in their right mind would ever let pantheon get his stun in lane. It would simply be "oh, he Q'd me. Time to play safe for a few seconds then kill him cause he has no stun and no Q".

It would also indirectly nerf his ult and late game. Right now one of the only ways Pantheon is effective late game is by ulting into the enemy team, and insta-jump-stunning someone. If that turns into ulting into the enemy team and insta-jump-slowing someone it would be significantly worse (think TF ult engage with red card.... not good).

I think the Impale mechanic is a neat idea I just think these changes would "Olaf" or "Evelyn" nerf pantheon. Instead of simply taking his current kit and adding a limiting factor make Impale limit him, but, also, give him bonuses if he uses it correctly. As you wrote it above all you are doing is taking his kit as it is, and putting restrictions on it. You are not giving the pantheon player a reward for properly using Impale. For example, if you get the Q->W combo it could apply a bleed, shred armor,give an empowered auto, convert E to true damage, raise the E passive to 35% health. You could have it grant any number of sucess bonuses. But, instead, it is simply a nerf as it limits what he already has with no compensation. Additionally, the ult problem could be worked around by guaranteeing a stun if Q is used during the animation of W or by adding a guaranteed empowered W after ulting.

I think you had a fun idea to 'correct' a champion that you don't like, but you didn't fully think through the ramifications of your proposed changes on the person playing Pantheon.