The energy-minimization multiscale (EMMS) principle of compromise in competition is believed to be generally applicable for all mesoscale problems at different levels in the real world, spanning from elementary particles to the universe. This stimulated a fundamental proposition of the concept of mesoscience. This article discusses a potential universality of the regime-specific multi-objective variational feature of this underlying principle through case studies in chemical engineering, and outlines the most important issues to be addressed in the field of mesoscience. It is also elucidated why the currently available variational principles are not applicable to the mesoscale problems. The paper concludes with prospects on future study.