Saving throws are pretty integral to D&D, that's why I wanted to have them. Not every bit of Magick the Mage uses would require one, but in most of the examples you cited, they probably would.
EDIT: My assumption was that making saving throws was a property of D&D characters, rather than a part of the Mage's Magick.
My idea for save DC was basically 10 + the Mage's Aretes + their casting stat.
True, but Forced Dream isn't that hard to manifest just before combat.
EDIT: You can augment it to last 1/min per manifester level, too.
Ah, OK.
So, mostly buffing and battlefield control.