My own tastes in magic lean toward the Hermetic and Kabalistic - that magic is at its heart a scholarly pursuit, and flexible in its implementation. This does not fit well with the 'pick most of your spells when you create your character' magic system in Fantasy Craft, so I use something else instead.
For the record, my favorite spellcasting systems in RPGs are those in Ars Magica, Rune Quest 3rd Edition, and for D20 style games Elements of Magic. All are flexible, and can support a scholarly approach to magic.
The Auld Grump
Are you talking about mechanics in which the players are able to create their own unique spells within certain boundaries or are you talking about the players having to only be able to learn the spells they come across in their travels (for example if they found a magical tome that contained spells they've never seen)?
The former. I much prefer a spellcrafting system to a simple rote spell based one.
As for @stroval's 'you can do it through roleplaying', I call malarkey. If you know most of spells that you will ever know before the game even begins then it is not
a matter of scholarship - you are not larnin', you already know
the danged spells. (And one of the main reasons that I do not use the Crafty magic system in either FC or SC2.0.) It actually rates slightly below D&D's magic system in this regard. At least in D&D when a wizard finds a spell he can attempt to learn it. In FC if he finds a spell then the next time he increases his spellcasting he can pretend to learn it, or pretend to learn any fershluginner spell he feels like, even if he can't cast it, and may never be able to cast it.
Fortunately, there are alternatives that I can do a quick cob job on, and get them to work with FC or Spycraft. So while I do not like the system it does not irk me in the same fashion that the Forge system does. While it actually annoys me more than the Forge, the fix is much easier. So, I can roll with what I prefer, and move on from there, blithely ignoring the Crafty system. Elements of Magic is fairly close to what I want, and allows for improvisational spellcasting. The fit with the system is not perfect, but the fit with my preferences is much closer.
The Astral magic system that Morg has been working on is a better system than that of base FC in some ways, even though it is less flexible. It just holds together better, it has better verisimilitude. Not a matter of learning spells, but of learning to use innate abilities.
I have also ported the magic system from Call of Cthulhu D20 to Spycraft, it works surprisingly well, substituting Stress damage for San damage.
The Auld Grump