I assume you're talking about visually we don't need tiers? Behind the scenes we'd still need to keep track of this in some fashion... or keep track of their amount of degradation, anyhow. Still being able to craft with them makes sense if you're getting a result that is then pre-degraded by a certain amount.
Yes I mean only visually you wouldn't need tiers, which would simplify keeping track of the numbers. From the player's perspective, he'd have degraded spell gems of various degrees, inferior spell gems (created from aged base gems) and aged base gems of various degrees.
One thing to be careful with is that if you allow crafting with aged gems, the result should be qualitatively weaker and preferably do less damage. Otherwise, let's say crafting with an old gem creates a spell gem that's just half degraded. I could hoard a huge amount of old gems and keep crafting with them. True, the life of my spells will be halved, but since I have such a huge stash it doesn't matter. Therefore the actual resulting spells need to be weaker or damaged. To simplify you could just prohibit using base gems that are more than X old.
Having random misfires and fizzles strikes me as something that would only be frustrating to players -- I expect to get the result I want when I use something. I'd guess that maybe when something is "sort of" degraded it should fizzle on every third shot, and when it's "heavily degraded" it fizzles on every other shot, or something along those lines. That way it's a predictable sort of fizzling that you can work around if you're inclined to do so, but there's a heavy incentive for getting something that isn't so cruddy.
I think this will only be acceptable to players if the spell gem is really in its last, dying stages. For the majority of its life (which could be around 5-10 levels or more's worth of fighting) the gem should behave normally even as it degrades. Anything less will give strong incentive to constantly hunt for new gems. Sputtering should probably even be avoided altogether.
However, if a player chooses to craft using old gems (assuming it's permitted) then I think all bets are off. As I said, you can't just make the spell-gem half degraded -- that can be abused. You have to damage that spell in a serious way, and one way could be to make it fizzle semi-randomly. That's a choice the player made knowing what could happen. In later versions, you could have some really weird entropy-type enemies that can ONLY be damaged by inferior (misfiring) spell gems (items affected by entropy).
Similarly, having spells just completely break and disappear seems undesirable to me, since then you could get into situations where you have no spells and no way to get more! Heh.
Good point. I guess spells should either become very weak when they're dead, or should consume a massive amount of mana.
It is true that spellgems don't really need to be droppable in the main. The two reasons arguing for it are:
1. Being able to give a spellgem to a friend in multiplayer, which is all kinds of useful (and which has the same exploits possible as just dropping it on the ground). I'm not sure how to get around this, but maybe it's not actually a problem.
2. Being able to clear out stuff from your inventory that you no longer want, since there are more spells and items than inventory space. But for this one, we could simply do something like having the item disintegrate when you drop it, and have the game warn you that's about to happen.
I would add to this the ability to have limited inventory. Right now that's not in the design, but I personally think it could contribute a lot to the planning and choice-making involved. If you don't allow dropping spells into some sort of stash, that rules out the option of having limited inventory if you want it later on. This is more of a design consideration than a real game situation -- the game will either have limited inventory or it won't. I'm just pointing out the design conflict there, and that by deciding one thing you're really deciding the other as well.
