Well the magic isn't limited in multiplayer, its the same exact system as in single play. It is what you make of it. The system seems like there could be alot of deapth to it but I won't know until I progress in the classes and learn more tricks.
Let me just explain how the magic system works so everyone can see how it has the potential for a huge set of magical tricks. There is a menu of magic linguistics, as they call it, which you are to combine in a series of 2-5. This combination is what creats a spell. I'll give an example in a minute, let me get into the different sets of linguistics. There is the BASIC linguistics that are 2 pages deap with each page holding 15 individual linguistic terms. Then theres the WHO set which is 3 pages deap, 15 terms a page. The DO set which is 2 pages, 15 terms a page. The WHAT set, which is 3 pages, 15 terms a page. The WHERE set, 3 pages deap, 15 terms a page. Finally there is the WHEN set which is just 1 page of 15 terms.
Now for the example, in order to cast the treasure hunt spell, which helps you find hidden treasure, you need to combine the BASIC term "Magic" with the WHAT term "Secret" and the DO term "seek". After doing so, this spell gets saved into your staff which you can then cast at any time. There are 2 types of magic in the game, Staff magic and incantations. I've only learned staff magic which is magic you can physically do but I assume incantations are magic that would affect the world somehow, maybe altering time or weather I guess.
Its not as complex as it seems, trust me. So as you can see, which so many different terms to combine and the many different posibilities for combinations, the amount of magic possible could be staggering. As I'm just getting into the game and the fact that it takes place in real time, its hard for me to see everything the game has to offer so soon. All I'm saying is that the game has huge potential.