I really hope magic will not be freeform, I much prefer codified lists of spells that players can cast and find; the latter gives them a reason to go out and risk their frail bodies to adventure, otherwise if they could just make their own spells they would rather stay safely in a tower and do research. Aside from spell lists I believe a system to allow collecting of spell regents to make spells more powerful would be great; it would give PC Sorcerers/Spellbinders more reason to adventure to find and collect these rare ingredients. Like maybe a rare Herb that can increase the potency of curing spells, or a dragons eye that increases the power of all fire spells by a large amount; ofcourse no dragon would willingly part with an eye so...
Another thing I would like is separate magic styles; an adventuring Spellbinder would need to have spells that suit an adventurer out in the badlands. So spells that are quick to cast and both utilitarian and combat focused, as well as defensive focused. However other NPCs in the game world such as city based mages or court mages would use a different, more traditional magic system that's slower to cast but has different, more grandiose effects. Spells of summoning daemons or other things for example, or spells to alter the weather, scrying, etc.
Finally I was not a fan of the small handful of Mutant Powers in MY0, nor the extremely small number of psychic talents/powers in Coriolis. Thus please, please please give players a large number of spells to potentially use in the game. One of the greatest fun of playing a mage is choosing spells and figuring out which/when to use it!
