I find the Mighty Lord of Khorne fairly lackluster in combat as well (which is why I don't take him), but his command trait is amazing. I usually go with either the +1 wound, or the Chaos Talisman for the extra save. They are all fairly the same.
The command trait, depends on the army. Destruction, I take the -1 to hit rolls for my opponents first turn, and the anti-Order one for games against order. Lord of war is a more reliable +1 to hit for a unit, which is really nice. I almost never worry about the Chaos Allegiance ability, it's great when it does work, but I wont spend a lot of effort to make it better.
I usually take a Bloodstoker, Bloodsecrator, and Slaughterpriest as my main 3 heroes. Bloodthirster of unfitted fury, and Skarr Bloodwraith as extra.