Pillager,
Yup, my AD&D sensibilities are indeed offended by the idea of Wizards in Plate Mail / Axes of Slaying just as much as they are by Fighters using scrolls. There are only 3 ways to deal with that issue. (1) Ignore this issue with items but not magic. Seems illogical but I suspect this is how it's going to end up. (2) Make all items generic enough to work with any hero class. That's boring and doesn't fit well with the item slots that I've seen for Beta4 heroes. (3) Customize the item to the hero who first finds it. By that I mean you'd have a generic Plate Mail/Leather Armor/Robe icon for the armor slot. Then assign the power+item name when the item is found. So lets assume you are finding a hits +1 armor item. If you were a Wizard it would be the Robe of Defense which gives +1 hits. If you are a Ranger, a Leather of Defense giving +1 hits and if you were a Paladin a Platemail of Defense giving +1 hits. That way you get the right item with the right hero. Once in the game the item is fixed and if you transferred the item or the hero died the next hero would have to be the right type to use it. The only issue with this is you can end up with heroes who have items they can't use but at least it won't ever be at the time you find the item which would be annoying.
I think balancing 1 shot items is indeed going to be very tricky. Plus it's just extra inventory you have to carry around, transfer etc. Much easier to just not have it at all as it's far easier balance wise to just say either 'I have this skill with this hero and I can use it or I don't'.
I agree the spells need recharge times. I mentioned that in my 3rd paragraph when I said you wanted to design around a spell recharge system. No need to work out individual details of that until you start on the spells themselves other than a spell slot is used up until the recharge time for the spell that was cast there ends.
I also agree the sage should give a skill selection list to chose from. It's always preferable to let players chose instead of being told what they get. The former is skill based, the latter is luck based. So I'd like to see 3 choices like 'You find a sage. He offers to teach you (A) Engineering 10% (B) Chain Lightning Spell (C) Group Move +4 spell'. Then you'd pick the one you want. Sages could literally teach any skill in the game so that all heroes would benefit so Fighters might get something like (A) Undead Lore (B) Strength +2 (C) Learning + 15%.
Obviously the better the ruin/harder the quest the better the sages teaching would be so a L3 ruin might offer Command +1 for Fighters or a really good spell for a Spell Caster like Summon Archon/Elemental.
KGB