Skills and Super Ability of the Orcs.

Siege engines are always a very useful skill for Orcs, and for the main hero as well. The exception is a very long game.
The statement that it's easy to kill is false. The ballista has 1200 hit points and good defense. Besides, it deals tremendous damage. Because flaming arrows are always learned for the ballista, and artifacts for luck or the luck skill itself are sought. Even if the ballista is destroyed twice, the opponent will take very serious damage. Luck will always trigger at least once, even if only on one of the three shots.
Warlock, yes. It's better not to take a ballista with him - he can destroy it with a meteor shower. But the other heroes will have problems. If some elf spends his archers' turn, it means he won't attack your units.
And the ballista is also very useful for clearing mines and finding artifacts, as is the tent.

Luck is a specific skill - it may or may not work. It's a matter of preference, that's true. But luck does trigger quite often. Especially considering that a clover or tarot cards are available on every map. Luck is a great skill for the main hero, and even more so because of the Soldier's Luck ability. This allows the paladins to deal an additional attack. Sometimes it happens that they attack up to 4 times in a row!

Battle Shout is a very valuable skill for the main hero, but it is rare. At first, I thought, why do they need it if shouts are learned anyway, regardless of this skill. But no!
Here are the advantages of taking Battle Shout:
1) Battle Shout doubles the rage points received from all shouts. And rage is the foundation of the Orc's life. The Horde Shout is simply magnificent. Because, in addition to damage, it gives all units about 100 rage points. Or the Blood Call shout, which gives one creature about 500 rage points, which guarantees a transition to the second, or even the third level of rage.
2) Shouts cost less mana, and some become free. Therefore, you can annoy both neutral and enemy heroes with shouts.
3) The hero, thanks to the expert level in shouts, moves much more often. And this is very valuable!

In general, you need to always take Attack and Leadership for the Orc - these are the two most important skills. Attack is useful in itself, as are flaming arrows or retribution.
In Leadership, you must definitely take Bloodlust. Even against a Necromancer. This is an invaluable skill, simply invaluable. Morale triggers almost every turn and increases rage. And thanks to the Unifying Shout, the Orc's morale is never lower than +8. And thanks to artifacts, it can be even higher.