"What is holding back Smalltalk?" may or may not be a legitimate question. However, the question is somewhat relative to the audience. On a Squeak mailing list, the answer to this question is straightforward: there is nothing holding Smalltalk back.
It would be more interesting to survey a general population (of developers) with both specific and open questions. This would also increase the "brand awareness" (Squeak and Smalltalk in general). A survey passed along to colleagues, teachers, classroms, etc., would certainly generate more interest, at low costs, and yet the compiled data could outline the "failing" aspects of Squeak or Smalltalk in general.
Anyway, it's just some thoughts...
Ian.