In Gen 1 and Gen 2, all stats could have their EVs maxed out, so balanced mixed attackers were actually very playable. Case in point? Surf Tauros in Gen 1 and Lovely Kiss Nidoking in Gen 2.
Gen 3 capped the EV spread, which was a huge nerf to balanced stats. Gen 4 then unplugged the then comatose balanced mons to their quiet death. Now, if you don't have min-maxed stats, you have broken abilities. If you don't have either, you're dookie.