skyjob:
You are correct that an EO does no take these into account, merely terrain clearance requirements. For best vertical gains straight out departures are usually considered to best as the aircraft does not limb as well during a turn, in case of EO may no even limb at all in a turn.
At many locations turns are required in OEI procedure. Track design is predicated on any turn being made at a 15 degree angle of bank, which results in very little loss of lift.