So I played a little of new Pantheon and from what I've seen from personal perspective and other people playing him in streams / youtube videos, I don't know if it's just me, but I get the feeling he is kind of bad. Now I did not check his curent winrate because that's what nerds do, real men find out if a champion is good or not from their own experience.
He is pretty much still the old Pantheon but now he takes some skill to play. Old Pantheon used to be a beast in laning phase while falling off late game and forced to build a little tanky. New Pantheon is meh in laning phase while falling off late game and forced to build a little tanky. New Pantheon can lose even to ''weak'' early game champions like Mordekaiser before his 1 item power spike (broken btw) and even Nasus at lvl 6 which can all in him with no problemo. Old Pantheon used to counter Renekton, new Pantheon gets shoot on by Renekton. His ult is pretty useless when it comes to AoE damage in teamfights since you will always do half the damage. Come on, no one will be in the middle of the area when you land, they will be out of it or at least at the edges, so they take 50% damage. They should make them always take full damage if they are still in the area. Late game Pantheon is totally useless, he cannot carry, he cannot do much in teamfights, he just goes a little tanky and stabs people with his spear every now and then (and ocasionally stuns and brofisting a Braum if he has one). Notice how I said *stabs* with his spear instead of *throws* his spear, because throwing the spear is useless! It does less damage to enemies beyond the first and it's so freaking easy to sidestep it, not to mention you get to wait the full CD while if you stab you deal the same damage to all enemies while refunding half the CD, and it still has a pretty decent range.
He is very fun to play, not gonna lie, but he offers nothing to his team (he didn't offer anything before either but he was so braindead you could play him anyway). There is no point in taking him, maybe dominating early game and still getting destroyed later by better champions who will automatically win the game cuz they are just outscaling you no matter what they build (looking at you, Kai'sa, a champion who can go 0/6 and finish 20/8 after 3 items).