Heres an idea instead of unsin fire against fire if thats all you have in turms of spells, why not use melle attacks... Give both spell levels and character levels as gaining xp, so that the character and become more dexterious and gain strength to use better weapons to attack the npc's.

Hmm.. One possibility is to add some kind of stamina value to each element. So every time you cast fire it does less and less damage while other elements stamina would return to normal.

This would mean the player would have to switch to using other elements ingame to recover stamina and thus level up more than one element.

Somewhat restrictive, but it could lead to some interesting battles.

Nope, you'd switch to Earth for a while which would also do damage (just not as much as full fire).

I disagree. Casting the same spell over and over again gets boring very quickly for me personally. I would prefer a system where I had to be more involved with trying to cast the best spell each time by varying the spells I cast and anticipating casting a more powerful spell in x turns.

Personally I'd prefer that to, "Hey! This is great I can cast five thousand fire spells and kill everything with only one spell. I'm a great RPG player!"

These are all theories, what we really need is a simple RPG battle engine to test these ideas out in. That would be a good way to judge the advantages and disadvantages of each idea.

Anyone up for making a quick and simple battle engine though?

There is surely someone here with time on their hands to do a quick battle engine. Heck even one on the speedhack entries was a RPG with a battle engine..

FFX-2 style. 3D.

I much prefer ATB style battle engines, btw - the element of time means you have to be more strategic and prepared for battle.

There's one big problem with maxing out one spell category: As soon as you encounter an enemy that is immune to that kind of damage (ice / fire / lightning / whatever) you're doomed.

If you're using just one spell / attack all of the time, the game becomes more like a shooter. That doesn't have to bad, though.
On the other hand, you don't need to wait until you run out of "specific mana" before you cast a spell of another type. Just mix the spells from the beginning. Cast a few fire balls, buff your defense using an earth spell, then continue to cast fireballs.

In that case you won't like many games
IMO there's no big difference between your example and the general "Oh, I've run out of mana. Now I can't cast any spell at all" and the example Rich proposed. Oh. There's one difference: Using a system like Rich proposed would allow you to continue playing

Another thing you need to keep in mind is that you don't start as an eliet wizard with 4000 fire spells ready. At the beginning you won't be able at to cast many spells of any kind.
So you'll get used to the spell switching while playing the game.

Now add some monsters which are immune to one particular spell effect and you'll need to plan your attacks more carefully. Which also allows you to add some nice stone-paper-scissors gameplay elements.

Some time ago I had a similar idea. But I planned to use one mana pool for all spells. Just the mana regeneration rate would vary. So, if you're a fire specialist mana you used for fire spells would refill faster.
My magic-theory behind this was that each player has a certain amount of mana potential which depends on the level of the character. If you cast a spell you create a mana difference between your potential and the elemental plane of the spell.. the more you're in "harmony" with that plane, the faster you can channel the mana back into your body.

I was also planning areas which are less atuned to a certain element. So, casting water spells while you're standing in lava deep inside a vulcane will work - but since the place is more atuned to fire and earth than water, you'll have problems regaining that mana you've just used.

Derezo: I haven't played a single game where you can boost a single type of spell while gimping others - have you?

Well, I don't read other threads.

And I never played RO either ...

Off-topic; but; did RO drop from beta and is now pay-to-play? How are the servers? Still slow as all hell? Hmm. I know I shouldn't do this and I hate people who do it but you know.

And the solution to this magic problem is to have the person who introduces you to magic say something like "Remember, moderation is the key!" or something else that would warn the player that maxing out a single stat is retarded and will retard your fun-having process later on in the game.

He should, because just being thrown in without warnings and advice is NO FUN FOR THE PLAYER, which is the main priority.

Having to level up spells mindlessly is no fun, regardless of whether it's the intelligent thing to do or not. You have to integrate it into the everyday hacking and slashing seamlessly, or the player WILL get bored.