Off Topic: bad sign when people has to start making necroposting to keep the forum alive...
I wouldn't say I'm doing it to keep the forum alive. It has been rather active of late. I just wanted to talk about it, and why bother creating a new thread where there was an entirely unused thread sitting back a few months.
As always balence is the key.
I'm not entirely sure if that is true. I mean, it certainly is in multiplayer, and I would like to try to create a balanced game. But frogboy said that Elemental was a mainly single player game, and he also said that late-game was going to have some intentionally unbalanced spells (provided everybody is equelly broken, we'd be in a good place). But I don't think balance is nearly as important here as it is in say... demigod or even Sins of a Solar Empire.
That being said, depending how structured the spell selection is, it might be able to create rather balanced spell sets and still include many combination. spells. The best way I see it, is stack the spells in research order from lowest level to highest level. A lightning spell that would require 3 fire tomes/levels, 3 wind, and 3 water would effectivly be a level 9 spell. So that should be a pretty darn powerful spell (assuming you rarely get over 10, as is the case with MoM) and as a result it would come very late game.
An average strength lightning spell might come from 2 fire, 1 water, 2 wind, and that would be about a level 5 spell. It should be arranged in the spell book with other level 5 spells in terms of research order, and be about as powerful as such. This makes sense for lightning to be stronger than the level 3 direct fire damage spell, because lets face it. lightning doesn't strike the same place twice, because the place isn't there for a 2nd time.
Steam burns are about the worst kinds of burns there are. (low level fire/water) and some of the combo spells I've thought of (boiling seas: for example) would be both very powerful, and I'd imagine requiring a lot of both schools.
So I think balance shouldn't be that much of a problem with having lots of combos. Combo spells would be largely late game anyway. The trick is if you have a crazy awesome 6 fire + 6 earth combo spell, you may want to be sure there is a crazy awesome 12 fire spell for the all-fire guys.
And reasonably, a person that is able to get 30 tomes/levels, to have 6 in every element... likely deserves something that is not obtainable by somebody that focuses only on a single element (assuming that at most you can start with 10 tomes) If you look at MoM, a person with 5 in every tome is almost hurt because they now get very little access to any of those "rare" spells that the specialists are swinging. Making a scale would probebly be best. 5 books = xx number of spells, 10 books = xx number of spells. And stick to that ratio no matter how many elements are included, again something MoM doesn't really do.