So all of Beta 1 consists of an initial magic system? Without magic spells (which are implemented in Beta 3)?
I think there is more to it.
1. Spells will have lots of flashy 3D particle effects that may not be available in the 1st 3D build. So while we may have spells by the end of Beta 1, they are likely removed again in Beta 3. They said one benifit of the cloth-map only is they can play with things without having to make expensive graphics, this is especially true for spell animations.
2. Custom spells, Beta 6 has some complex custom stuff, but I think its safe to assume that some custom things like spells, magic, and maps will be implemented prior to that. they already have people making custom spells (see original countdown to beta release where they had the artists make some spells) so chances are that may be one of the 1st things we'll be testing for custom functionality. (right after custom tiles, which I suspect will be in the 1st 3D build since it seemed to work just fine at PAX)