Few questions about skills.

Tristis Oris

I know that somewhere there are answers, but they are hard to find everything in one place.
1. Class skills it a spell? (Templar's Aedric Spear, etc.)
2. If it a spell - Jaggernaut passive bonus a useless for this? (This is logical because they use mana, but the game is too many strange things)
3. If it a spell, attack modificator of weapon don't work for them?
4. "Power" and attack of weapon are equivalent?

I know that DD is desirable to walk in light or medium armor bonuses due to mana or stamina, but also i do not want to die by running into a magical robe, so I do think the 5 +2 or 5 +1 +1.

Nasuradin_ESO

All class skills use magicka and all magicka-using abilities scale in damage with your total magicka pool, as far as if melee-range class skills are effected by Juggernaut's melee power passive, not sure at all. All weapon skills except the obviously ranged ones (staff and bow) probably work with juggernaut.

Tristis Oris

Thanks. then it makes no sense to wear heavy or medium armor, if I make it a priority to class abilities? or better to use weapon abilities.