Crusaders are by FAR the most numerous (plus 2 large castles and 4 small wall sections), but the Crown knights admittedly have a *dragon*. The Lion Knights, Black Falcons, Wolfpack, Royal Knights, "Green Dragons", Leo's Knights, Bulls, Black Knights, Classic Castle Knights, Forestmen, Dark Forest, and Dwarves are just outnumbered by the Crusaders, hands-down. Wouldn't stand a chance individually. The Dragon Masters, Fright Knights, KK2, Shadow/Rogue Knights, Undead, Crown Knights, and Trolls all have some sort of magic and/or fantasy stuff going for them that COULD make them victorious, depending on your interpretation.
I actually set up a series of BrikWars games (as of yet not concluded) to see who would win between the "classic" factions (up through 1999). With BrikWars rules, the Fright Knights are the favored winners.