I like to think there's a reason that powerful mages don't often run roughshod over the world - it's because magic is dangerous stuff and if they don't eventually screw it up (consider the primary cause of mass wasting in mountain chains is not erosion...) they usually go crazy. Giving up on Vancian magic does not mean that you have to neuter the magic of a spell system. Yes a lot of this relies on the campaign setting, however in the rules I wanted to make sure that there was some reflection of this - so there is always a dice roll for casting a spell. Along with a dice roll comes a critical hit/fumble table as well.
Also a personal peeve of mine;
Whenever I have someone look at Beacon (or Microlite) one of the first comments is "I don't like that magic uses up your hit points. I think that will make players not want to cast spells."
I just don't understand this comment because having a fixed number of daily spell slots will also make players not want to use spells (especially once they have used all their daily slots up). Here's a clip from a email I sent to doubtful friend of mine (who shall remain nameless for now!)
Figure that you are a mage with a STR of 13 and you get a 4 on your <hp> roll so you have 17 Hp which is pretty average. A first level spell costs 3hp to cast and cantrips like the light spell cost 1 so at level 1 out the gate you can cast light 3 times, magic missile and 2 sleep spells (1+1+1+3+3+3=12) and still have 5hp left over before you pass out. If you get to 0hp you still have 13 STR before you die. If there was a real emergency you still can cast one first level and one cantrip and let the heavy carry you back to town and you get all your HP back after a good 8 hour rest.A Beacon mage will generally have more spells available to cast than their d&d counterpart, as well as be more useful when not spell casting due to the more flexible skill system. Some of those spell might not work, there's a small chance they may work at double or even triple levels of power or they might even backfire and scorch your MIND.
That's way better than old school d&d where you would have one sleep spell per day*.
SO you get more spells my apprentice - but they will come at a price! Mu-hahah<cough>haha
*and probably 2 HP --- in your face!