By thinking of it.
Monsters in the MM ,IMO, are usualy part of community so they have learn they way of fighting, knowledge.... in this case there basic bonus.... but take a monster such the gnoll
Medium-Size Humanoid (Gnoll) (ok)
Hit Dice: 2d8+2 (11 hp) (Basic gnoll warrior training)
Initiative: +0 (ok)
Speed: 20 ft. (scale mail), base 30 ft. (ok)
AC: 17 (+1 natural, +4 scale, +2 large shield) (ok)
Attacks: Battleaxe +3 melee; or shortbow +1 ranged (ok)
Damage: Battleaxe 1d8+2; or shortbow 1d6 (ok)
Face/Reach: 5 ft. by 5 ft./5 ft. (Depend)
Special Qualities: Darkvision 60 ft. (ok)
Saves: Fort +4, Ref +0, Will +0 (Depend)
Abilities: Str 15, Dex 10, Con 13, Int 8, Wis 11, Cha 8 (Can be reroll)
Skills: Listen +3, Spot +3 (Can be taken out)
Feats: Power Attack (Racial feat)
So here what would like a gnoll with no ECL
Medium-Size Humanoid (Gnoll)
Hit Dice: By Class
Initiative: +0
Speed: base 30 ft.
AC: 11 (+1 natural)
Attacks: By Weapon
Damage: By Weapon
Face/Reach: 5 ft. by 5 ft./5 ft.
Special Qualities: Darkvision 60 ft.
Saves: By Class
Abilities: Str +4, Dex 0, Con +2, Int -2, Wis 0, Cha -2
Skills: Listen +3, Spot +3 (racial)
Feats: Power Attack (racial)
Would this race would be more powerfull that the human (Bonus feat, bonus skill) or elf (bonus listen, spot, will save)