I would cut the natural armor to +2, because a full ogres nat. armor is only +5. Totally agree with you there.
As for the size / reach I have no problem; being large gives you a -1 Ac, -1 to hit, and if I recall right a -4 to hide checks. Penalties to two potential casting stats (int, cha), and their +6 str / +2 con is less then the bonuses a normal human would get if they were increased to large size; med to large is normally +8 str, -2 dex, +4 con, +2 natural armor. Compared to the other +1 ECL races I can think of off the top of my head, they're not that bad. No skill bonuses, no save bonuses, not native outsiders, no elemental resistances, no innate spells. Heh, besides by the time the sorc/wiz in the party has access to Poly Other the tanks can have reach, higher stats and better nat armor with no drawbacks or ECL by turning them into normal ogres or smaller giants.