See Pantheon's problem is that unless your enemy made some really dumb mistakes and fed him early, Pantheon's ability to carry is completely based on getting his allies to carry him. His ult is fantastic for giving Bot kills and letting Bot carry you harder.
Because of this, his winrate has kinda reversed. He used to have a high winrate at low ranks because he was one of the top 3 lane bullies and a poor winrate at high ranks because, well, he's easy to counter if you know what you're doing. Now, because his lane phase isn't actually good against the Meta picks, Doran's Shield+Second Wind counters his poke completely, that means he has to play completely differently.
It just so happens, that his other way of playing: safe farm with your Q then ult Bot lane and feed your carry early kills, is now his winning strategy. And he has higher winrate at higher ranks because they have the skill to actually coordinate with their Bot Lane to do it. And since right now, ADC's are basically the means of winning the game that's his dominant strategy. And he does it very well.
Riot mentioned the potential Pantheon buffs while this transition was still coming about. So, I don't know if they'll carry through with it. I'd personally enjoy seeing his ability to actually carry on his own being increased, while maybe toning down his ability to snowball Bot lane. But, that would probably just be a nerf in the current Meta. One that would make playing Pantheon feel better, but would also make laning against him even more miserable.
