- Tactics skill in Heroes 3.

No one has mentioned one of the main (and not so obvious, like contextual help) advantages of tactics – a more convenient arrangement for flanking. Very good players can flank anyone even without tactics, but even with group golems, I struggle without tactics – they just charge forward. And there are also trolls – once enraged, they can reach the stack of archers on the first turn; with tactics, you can not only provide basic cover but also direct the enemies in one direction, divide them into parts, and, if you're lucky, detach a single stack from them. You can use the terrain, position units – for example, place slow dragons for self-buffing or a mass attack (not very reliable, depends on the AI and the player's skills). Therefore, this skill is even more useful for non-ranged troops.
Often, tactics are more useful than mass slow/haste – if you have strong melee units/archers/no mass haste, I would prefer tactics over logistics.
I'll risk bringing up an old topic – tactics, like mass slow, and starting with conflict axe/rampart, are less relevant with high skill. For example, a bad player needs mass slow to capture the conservatory, but an average player doesn't.