The problem with Large races in 3.x were (1) reach and its powerful synergies with AoOs, spiked chains, and Combat Reflexes, (2) big bonuses to combat maneuvers like trip and grapple, and (3) their tendency to have large Str bonuses as well.
In 4E, a Large race would get the ability to wield weapons that do more damage, defense against some powers that require the target be within 1 size category of the attacker, and Reach 2, which does not apply on opportunity attacks.
A half-ogre could easily be balanced similar to the minotaur, I think -- +2 Str, +2 Con, Large size (which would more or less equal the bugbear or minotaur ability Oversized Weapons), +2 to two skills (Intimidate and Athletics/Endurance maybe?), and probably a racial encounter ability on the weak side (to balance the few corner case benefits that Large size could provide).