If the theory does not meet the standards of theory building, it is unlikely that research will lead to any useful insights. If the research design does not meet the standards of good design, the potential for arriving at useful findings is limited. If both theory building and research design are faulty, the resulting data is likely to have little meaning. These are serious substantive issues and most of your attention should be given to them. Substantive theory, familiarity with relevant work in the area and cognate areas .
Most work builds on the foundation of previous work.
To the extent one is inadequately grounded in previous work, the potential for additivity is low. Refer to specific articles, books, or material that would be helpful. It is not very helpful to observe Your grounding in the literature is weak, fragmented and superficial. Or, you are overlooking important work in the area that contradicts you thesis and conclusions. Refer to the specific work that you have in mind.