Lemme just clarify my thinking when I say that a +4 to an attribute should automatically make that race a +2 ECL.
Attribute bonuses are HUGE advantages. There are ways to get around the absense of to hit bonuses (more str) skills (more int) hit points (more con) and so on and so forth.
I pretty much look at the ECL balancing as such:
+0 ECL - max of +2 to an attribute. Must be balanced by at least a -2 elsewhere. Instead of an extra human feat, skill points, and multiclassing ability, minor abilities such as +2 to +4 skill bonuses, darkvision, and limited +1 saving throw modifiers may be added. A high bonus in one area should generally be negated in another area. (+1 saving throw bonus should not also allow a +4 skill bonus, max the race should have would be +2)
+1 ECL - max of +2 to 2 different attrbutes. May have higher saving throw or skill bonuses, up to +4 to +6. May have limited +2 saving throw bonuses. Minor spell-like abilities, such as cantrips and level 1-2 spells can be added. Level 1 and 2 abilities should be restricted to 1/day, cantrips generally 3/day. More powerful spell like abilities and skill bonuses should be balanced with the attribute bonuses and penalties.
+2 ECL - max of +4 to one attribute, and a net bonus of +6 attribute points maximum (ie +4 dex, +2 con and +2 str must have a -2 in another attribute). May have a minor global bonus to saves, or a major limited bonus to saves. Moderate abilties such as flight, Spell Resistance, enhanced movement, natural weapons, and natural armor are allowed. Natural armor and weapons should generally be restricted to +2 AC or D6 damage. User may have more spell like abilities, or a single more powerful spell like ability, generally up to level 4. More powerful spell-like abilities or natural abilities should be kept balanced by lowering attribute bonuses, saves, etc.
And so on and so forth. I think this system is at least somewhat similar to what Wizards uses when trying to keep the power levels of +ECL races at least somewhat similar.