We know that smaller class sizes and classrooms designed for active learning give better academic outcomes (S. Cotner et al. J. Coll. Sci. Teach. 42, 82–88; 2013), yet budgetary pressures discourage institutions from abandoning big lecture halls in favour of small classes.
Also, there should not be separate faculty tracks for teaching and research. Teaching positions rarely include research support, so they do not offer the same academic opportunities as research faculty positions.
These issues are ultimately about institutional and administrative buy-in. The success of STEM students depends on institutions investing in improved learning facilities and on administrators providing research, tenure and promotion opportunities for those who teach.