The issues I've seen with units playing as an Orc (which is all I've played at this time) is:
Goblins Spawn Bug (I actually destroyed all my Goblin Tents to prevent it because I was Getting about 11 Raider spawns every time I did a mission - yeah I had that many tents). The tents add more resource capacity to the city than the Hut. Also, for cheap expendable units they are good as all my other units except Ogres require upgrading other unit types all of which come from the laborer/marauders that spawn from main hall/keep or need to be purchased as mercs.
It would be nice if Huts (regular) added a bit more resource capacity and could spawn Laborer/Marauders. Presently, all Orc spawn building require a lesser units to spawn a unit, causing the Main Hold spawn rate to gate spawn rates for all the Orc spawning buildings.
Wargs need to move a lot faster (they are as slow as my Siege units). They need to be levelable - presently they are not, I purchased some level 4 Wargs and couldn't level them. The fatten commands should be in a sub-menu not the main unit menu.
Goblin Upgrade glitch - I swear the Health on my Goblins went Down (144 before, 140 now) after getting the goblin upgrade that boosts Goblin stats (health, Speed, Accuracy).
Goblins - Adding a Wolfrider or Warg rider goblin cav unit would be nice - maybe a mounted archer but that may be too powerful. Stealth if possible should probably replace Evasion since it seems to accomplish the same thing.
Presently, due mainly to the bugs, Goblins and Ogres are more prevalant in my armies than Orcs due to difficulty creating Orc units and my Cities pop being capped at 90 regardless of how many huts/tents I have (I have yet to upgrade to Wooden Halls-Fortress yet - only have palisades due to issues with quests and OOS with PvP matches and inability til recently to level units without sieging cities by viewing and slaughtering/farming on the World Map).
Can't really say anything else about the Orc units because I've so little experience and opportunity to use them. Would be nice if the Hero unit could be customised/altered (ie. changed to a mounted unit/Pike/Ranged etc. type in the Player city without losing his level).
Though, the bugs and glitches with the UI - commands working and such take greater priority.