Too little, too late. Disney's penchant of buying a franchise after they have peaked (Muppets, Infoseek) shows their lack of confidence in their own creative abilities.
Disney USED to be able to take a concept and mold it into something uniquely Disney (Snow White, Peter Pan, Alice in Wonderland, Aladdin, Beauty & the Beast, etc.). Now they appear to just want to buy other's capabilities (Marvel, Avatar, Lucasfilm), cut and paste the Disney name on it and let it go at that.
Yes, they will probably parlay much off of the film library, but what will they actually be able to develop from Lucasfilm itself?