I finished Single player some days ago on commando and frankly... it was a piece of cake most of it... I finished it in something like 3 days (de'ja vu from RA2) and the only real hard mission was Stomping on holy ground (last mission), Petrova was hard only because she was surrounded by dozens of other units that kept spawning (the stealth soldiers never run out in there so don't try to take them out first from the tunnel).
Does anyone else thinks the same?P.S if anyone needs help I would gladly give hints etc' for your problems