It would need to be done in a way that lets people integrate them however they want but they'd be no harm in doing quest treasure cards for them as an option. I had a storm wizard that was specifically designed for them so he gets all element sets but lower movement and 3BP/7MP. If it turned out to be a bit op I was going to make combining cost 1MP. I also had it in my leveling system for the standard wizard, the basic version at veteran, the three in one spells at master and the rest at legend.
I don't remember the rules you changes exactly, I've got it somewhere on my computer, I'll find it later. I just remember that I though the spells where more fiddly than before. One of the best things about it I thought was how simple the combined spells were (and how simple is it implement them) yet how well it works with the theme of the new spell and the effects of the two that make it up. Most of them just take one of the spells and make it anywhere on the board and target a whole room. Lullaby is anywhere on the board because genie is and it's the genie that's casting it, backdraft (still my favourite and the one that sparked the idea) is anywhere on the board because fire of wrath is, cyclone is anywhere on the board because pass through rock literally allows the tempest spell to pass through rock.
I remember that the healing spell is quite weak, it just allows a full heal. I thought about rising BP and MP above the maximum and maybe having them drop by one each turn until they're back to normal but I think a better idea might be to include that it dispels any hostile spell effects they might be under as well as the heal. I renamed that spell so it matched the US potion that had the same effect but it should have a different name with a different effect. Restoration and rejuvenation are take though, er purification. I also think maybe combining all three spells in a set should cost 1MP.
Should start a new topic for this...
viewtopic.php?f=38&t=4296