Tell me about it, meleers hate that Sturmherz used reach and flying above his enemy before, though he accomplished it with glide speed from dragonborn wings and insane jump+natural elevations to get the height. That concept will certainly work against many melee fighters, but you still need to win a fight for the potion first or hope they don't bring a reach weapon themselvesA 15-20 reach will cause a lot of problems when I'm 15 feet directly above someone.
as for commoner + reach, my commoner has 20 feet without potions, though of course lacking the flight. I could have given him Starspawn instead of Deepspawn for unlimited average flight with landing every 4 turns or so. But I just liked the tentacles too much
Would be kinda funny if our two commoners run into each other in an official Round