As an Assembla user I fear they are not focusing on their core product. They have some weak areas in Assembla I wish they would focus on instead of reinventing the wheel.
I have the same concern. At Assembla, we feel that we need to work on being best of breed for repositories, and ticketing / issue management. Some of the collaboration features are not at the level of single-purpose providers, but we include them and incrementally enhance them because we think it is important to get project IP in one place. So, that is the focus that we have chosen. I am sure that we can be more focused. Please send us a note if you have specific areas of concern.