And skills shouldn't be chosen based on an either/or principle. They are usually not interchangeable; you need to choose based on the map (oh, how useful a scout can be on grass or at sea!), your troops and heroes, and the enemy's troops (how well skeletons fight under a Berserker!), and the artifacts you've obtained. You got Armageddon, picked up a lollipop - and go ahead and crush the enemy's Necromancers. And in this situation, how can you do without attack, shooting, and tactics?
Справочник по НоММ-4 http://handbookhmm.ru/pamyatka-dlya-heroes-iv.html
Памятка по НоММ-3 http://handbookhmm.ru/pamyatka-dlya-homm-iii.html
и HotA http://handbookhmm.ru/vyishla-obnovlennaya-pamyatka-dlya-homm-iii-hota.html