Increase Spell Maximum?

I can't get more than 5 spells on a hero. Can you increase the number of spells without creating a spellbook?

I'm not sure how to do it but you can get 7 spells on a hero I think. Something along the lines of...
1 ultimate ability
4 hero abilities
2 normal unit abilities

Yes, but the other methods are usually worse than creating a spellbook