honestly, i don't see the phlog OP, i mostly just see people, too dumb to understand how to deal with 'em.
Really, its simple, in most cases, gtfo, run like fuck back to your team or somewhere safe, use whatever movement tools you've got if any.
sniper can charge up a shot, soon as uber fades *BOOM!* easy headshot, pyro's gone, demo can set up a sticky trap 'round the phlog pyro, ka-boom! Soldiers, demos, FaN scouts, and non-phlog pyros can all use their weapons to knock the phlog pyro around/back/into hazards, i.e. sentries, bottomless pits, Saws, etc. Hell even Bonk scouts can drink up and block the phlog pyro for a while, Effectively wasting that phlog's Mmmph.
There's just so many ways people can counter a phlog, yet half the time they're just too dumb to understand or do it, Comms are important too, if your team's nearby and a phlog pyro's 'round the corner, warn 'em about the bugger, least then they can be ready to do something, be it retreat, readying their weapons to move 'em down, etc.
So no, i don't think its OP, Cause even then, pyro still has to get up-close And personal to even do anything, like they normally have to do, its your own fault if you get caught by 'em.