Personally, I think that the spells should be used primeraly in combat. I definately agree that Link shouldn't be turned into a spell caster, throwing fireballs at everything, but I really thing that spells are far better suited to tactical uses as they were in
AoL and LttP.
Useing spells mainly for puzzles is honestly a waste of their potential, there is no stratergy to it, it simply makes the puzzles mandatory and means that you need to use more magic (which will have to be supplied to the player if they want to solve the puzzle).
I think the opposite approach shoudl be taken, magic should seldom, if ever, be used for dungeon puzzles. It's purpose should be to act as a set of limited suplementary abilities to aid your sword play. A certain spell may increse your defence for a limited time, send enemies flying, teleport you or any number of uses.
It should be limited though, you should not be able to get a ton of magic jars for cutting grass and breaking pots all the time, you should have to earn your MP.