There’s tons of released stuff in the Early Access devlogs and plenty of situations where on old streams or at events like Gamescom where Joel would talk about sorcery. For the longest period of time the main thing that was holding back the development of the system was that Funcom couldn’t find a dedicated fx artist to do their vision justice and with something like this they didn’t want to half-■■■ it. Which later turned into more of a feature that would require way too much in the way of resources they had at the time to properly implement as they wanted, hence it being postponed indefinitely. Operative term there being ‘indefinite’ as they know it’s always being asked about but they don’t talk about anything anymore unless they have something to show for it (which is a very reasonable position).
It was never going to be throwing fireballs and I doubt it would have even resembled anything like the mage vocations in Age of Conan - barring some of the stuff that the Herald of Xotli utilized.