Which artifacts are best to equip a hero with?

I think morale-boosting artifacts are very important – because leadership is good, but it doesn't affect the heroes – and usually, there are 3-4 heroes of different schools and races in the army, and their morale is often very low. But artifacts affect everyone. By the way, I noticed an interesting thing – (I don't know if it's a developer error?): if, for example, there is a tactician with leadership in the army and another hero (it doesn't matter), and the tactician raises morale and luck, say, by 2, and the second hero has a morale or luck artifact in his inventory, the properties usually increase them for the entire army. However, in this case, the artifact doesn't work – that is, the effect of the artifact and leadership are not added together (ideally, they should be!) – it only affects the heroes, and only leadership affects the creatures. But if we give the famous artifact to the tactician, the artifact will work as it should – i.e., for the army, artifact + leadership, and for the heroes, only the artifact! That's how it is – so you should always give such artifacts to the tactician (if there is one, of course).