Secondary skills in Heroes 3.

In my opinion, leadership and luck are USELESS!!!

Thanks, you made me laugh :).
Of course... there's absolutely no difference whether your unit moves once or twice. It doesn't give any bonus at all :D
And if the creatures are of different alignments...
And luck is also completely useless :D. It makes no difference at all whether you deal 100 or 200 damage :D

Leadership, just like luck, is very useful.
Of course, it's useless for Necromancers to take leadership (considering that they will only have their native troops, which is unlikely).