I am biased against the use of mixed methods in research for some reason. In essence ‘sequential exploratory’ design is quantitative research while ‘sequential explanatory’ is qualitative; I have yet to see a convincing example of the ‘parallel sequential’ design. We do qualitative research to solve a problem (theoretical abstraction/theory formation/innovation) and quantitative research to see if the same abstraction can be applied to other situations (theory development/generalisation). Why on earth would a researcher want to solve a problem and generalise it at the same time? And why would they generalise something first and then interpret it, keeping in view that the interpreting (body of knowledge) already exists?
However, the worth of mixed-methods cannot be denied in developing quantitative methods tools. What are your views, please?