Reminder: Pantheon falls off hard late game and is not considered a late game carry in any sense. This is why it's really important to play the mid game correctly. Late game Pantheon becomes a front liner in most situations.
Does New Pantheon fall off?
Ever since Pantheon's rework in Patch 9.16, he's become an entirely new beast. He still maintains a semi-global presence with his R, Grand Starfall, but now he doesn't fall off moving past the early game. Pantheon is reliable, offers plenty of damage, and can go just about anywhere.
Is Pantheon good right now?
Pantheon is currently the perfect flex pick in solo queue and sometimes sees professional play as well. He sits at a 51.68% win rate in the mid lane, while he wins 50.55% of all games in the support position.