Raving Toy Maniac has just posted their Star Wars Q&A with Hasbro for this month, and it reveals a tiny bot about the future of the Star Wars Transformers line. There will be no Transforming Droids!

Any chance of seeing Droid based Star Wars Transformers, like an R2-D2 or C-3PO that convert into something?

Answer: It's a matter of size, character expression, and natural fit between the modes. First, R2-D2 and C-3PO are already robots (well, droids). Generally, Star Wars Transformers make sense in the film context with their character tying into vehicles with which they are associated and there aren't any good ties with the droids and vehicles that are compelling (other than perhaps R2-D2 and a Starfighter). In addition, while R2-D2 would be our first choice, a robot mode for him have to change his silhouette significantly and would not really deliver on R2 that we know and love. That's why the humanoid characters work the best.