1) This is pretty neat.
2) This is actually pretty similar to what's been suggested for Type 5 D&D cantrips, which I have previously derided in casual conversation.
The reconciliation between these two is a matter of the proposed Type 5 cantrips and the DCC magic system having the same basic philosophy and slightly different implementations -- the key here is that while both systems allow for repeated casting of spells over the course of the day, there is more risk to the DCC system, where even if Magic Missile always hits, you still have to roll to be able to cast it, with the possibility of wiping out your capacity to cast Magic Missile for the rest of the day.
(Obviously D&D Next is still in the playtesting phase and it's quite possible that they'll move to something similar to the DCC implementation.)
So, I've been thinking about making spell-casting in my Labyrinth Lord campaign more like DCC spell-casting. Because of the differences between the systems, a straight transfer of the mechanics won't work. Here's what I've come up with as a compromise:
Casting a spell involves rolling a d20 + either your Int bonus (magic-user, elf) or your Wis bonus (cleric).
Results go as follows:
1 - Spell has a Catastrophic Failure, is lost for day
2-5 - Spell Fails, is lost for day
6-9 - Spell Fails
10-15 - Spell Success
16-19 - Excellent Spell Success, caster can increase one aspect of the spell (i.e. choose one from does one more die-step of damage/healing, increased range, increased area of effect, more difficult to save against, etc.)
20 - Amazing Spell Success, select three from the above list or describe something aaaaaaaawesome
One thing that I've been thinking about is having healing/laying on of hands exempt from the "lost for the day" stipulation, under the theory that just having a chance of the spell failing is enough of a risk, plus the possibility of a Catastrophic Failure (which would almost certainly be deity disapproval) and having it lost would lead to too much "well we retreat and wait" activity. Although this makes me worried about the Cleric becoming too medic-ized, really, I don't think it can be worse than the shotgun-spell approach. I think it'll help with magic-users and elves as well, since now they won't be one-shot Sleep merchants and if they do lose Sleep, they'll be more likely to continue, just being more flexible with their other spells.