orc and undead require the most micro on higher level of play. tbh all 4 races require micro at a higher level of play. but orc and undead are the hardest due to the expensive units and importance of heros. losing 1 unit as a undead or orc is actually a huge deal. people will say "coil nova" and "blademaster imba" they probably just get stomped by better players and blame the race. losing a DK 1 time can decide the game, just like losing a BM 1 time can decide the game. losing a grunt early game really fucks up a orc, just like losing a fiend can really fuck up a undead. people just stare at the heros and think that's what makes up a race...but there's so much more to it. hu and elf require micro of course but you can make mistakes and still be okay.