well i dont think it states anywhere Lucas is writing the SCRIPTS--if i recall it is said he is writing the STORY, as in sketching out an overall plot and then letting writers pen the actual material. I believe this is the way Young Indy worked as well. Basically they are shooting it the same way--all the episodes will be filmed at once over a two year period, in effect producing a 50 hour feature film. Thus, the general storyline will be written out beforehand, by Lucas, and then the writers will come in and basically expand it into a couple seasons worth of actual scripts.
If this is the case, and i believe it is, then it can only be a good thing. My only trepidation on the series is the concept itself--maybe the low-bdugetness will make it look cheesy, or we'll know too much info about the GFFA or something. I dont know. Like i said, it has the potential to be very good so we'll just have to see. Would be cool if Vader made cameo appearances sporadically through the series, just for a few scenes, which I'm sure will happen.