Dragon Disciple's current epic bonus feat list is the following (per the Wiki):
Epic bonus feats: armor skin, automatic quicken spell, automatic silent spell, automatic still spell, epic damage reduction, epic prowess, epic reputation, epic spell penetration, epic toughness, greater spell focus, improved combat casting
Epic Weapon Focus seems like a reasonable addition since most Dragon Disciple builds are forced into going melee due to how it scales sorc.