1: What is the most interesting/exceptional spell in the game according to you?
invoke is by far the most interesting ability imo ^^
2: What non-ultimate spell would you say is the BEST in the game (don't consider the hero it's on just the spell by itself)?
holy persuasion
3: What four spells would you combine if your objective was to make the most dominant hero with the highest winrate?
IDK I'd have to think about this for a while, and I'll get back with you.
4: Is there any heroe(s) that only work in competitive/public games and why?
yeah I don't see sniper, pa, void, and huskar in competitive play because they're easily countered and
**** with good coordination, and in public games it's rare to see chen work out well because he falls off so quickly, and the only way to make up for that is high amounts of coordination from the start of the game leading towards a quick victory.
5: What hero requires the most skill to play properly? (apart from the obvious ones invoker, pudge, potm, geom)
chen
6: What's the most common and devastating mistake people make?
Picking carries instead of supports. Or picking supports and trying to carry.