In second ed I would say that strongest classes are mage > fighter > thief > druid > cleric and in 3.5 it's Cleric > Fighter > Thief > Druid > Mage (4th ed doesn't exist)

In 1-2 a level 20 fighter with the 20th level right equipment rules the game. Hand of Vecna + Blackrazor + Sword of Kas (dual wielding) + Ring of regeneration + Full Plate +5 + Amulet of Magic Resistance will beat in any other build. The way to make an interesting fighter is to give them interesting equipment.

On 3.0 it was neigh impossible for a mage to complete a spell -- everyone got free attacks of opportunity so the mage really become a glorified gunslinger. You spend all of your experience points making wands while the rest of the party continues to level up. Fighters have whatever options their feats grant them -- a fighter with a trip attack and a positioning feat will defeat any mage.

On 5th the weapons master has more options a mid level than does a mage.

I think the PoE fighter is the 3.5 fighter with a soupcon of 4th edition.

But, yeah, having said that I would never chose play a single class fighter with mundane equipment in any edition. Boring. I don't know why anyone would chose to play a single class fighter in any ruleset.