Sufyan: 4.) An apocalyptic event destroys most life on earth but also unleashes magic in various ways. I just love the idea of exploring humanity and civilization after an apocalypse, and I love the idea of exploring what would happen if people developed true undeniable magical abilities. 'What ifs' are what makes for good sci-fi and post-apoc and magic are two excelllent modifiers to our social and technological order.
Would remnants of old superpowers try and capitalise on magic? Would some societies shun the practise and those with proficiency? Who would be lost in history, who would spring out as new contenders, and who would seek to lord above all?
Of course, there is the question of just how powerful magic is. Magic, as I described in the post above, would be relatively tame power-wise and would be risky to use. In other words, not having magic would not put one at an extreme disadvantage. In such a world, magic would not be the best path to becoming lord above all. On the other hand, if magic were extremely powerful, then the world would be radically changed, and anyone who can master the art could take over the world. As one can see, a decision like that has enormous implications for world building (not to mention implications for game balance: If healing magic is powerful and risk free, why train in non-magical healing?)
A very different setting I would be interested in seeing is a common magic setting. In other words, magical ability isn't the sort of things that requires a special birth or training to do. Magic becomes a daily element of life, with people using minor electrical magic to power appliances (if technology exists and is common), fire magic to cook food, and so on. In this setting, *everybody* would have the capability to use magic, and if someone is unable to use magic, that person could be ostracized and bullied because of it. (The PlayStation game Saga Frontier 2 uses this as a plot point, except that that game has only medieval level technology and steel, the highest tech thing you encounter, tends to interfere with magic.)
Not enough settings handle the interplay of magic and technology, and of those that do, they are often in opposition. Where is the use of magic to power technology? Where is the idea of combining them? (Actually, Final Fantasy 6 did the latter, but you don't get to use MagiTek Armor enough in that game.)
I described low level electrical magic as making certain things malfunction, but now that I think about it, it could also be used to power such devices.