Tenure Track System has always been a debatable issue for the disciplines of Social Science and Humanities, particularly in the universities having very limited resources and lack of research culture.
Is a good question. Policy makers in education and higher education should have a comprehensive program for education and research in the humanities and social sciences;To be aware of all needs. Designing a comprehensive education and research system can be a good and effective way.
Your question intrigues me because of the need for a definition of what "effective tenure track system" might mean. As I understand it, the most common defense of tenure is that it undergirds academic freedom, so by this measure, an effective tenure track system would be one that most strongly precludes the possibility of sanction or termination due to unpleasant opinions or controversial research effort.
That being said, you seem to be linking tenure with research productivity in your question since the context is social science/humanities research in resource limited contexts. If you are seeking answers regarding which tenure track system might be most effective at stimulating research productivity, then that is a completely different question.
We all know tenured professors who have all but abandoned their research agendas. I would suggest that a system of employment preferable to the tenure system might best developed by the extension of five-year contracts that would intentionally permit the institution and the researcher to consider specific and measurable research goals in sequential contracts. I think this kind of system would be more effective in promoting meaningful research by more seasoned and experienced researchers, regardless of the resources available to support such efforts.