The Center for Budgetary and Strategic Assessments (CSBA) recently did a study which analyses over 1,450 air-to-air victories starting from 1965.
The author concluded that future American warplanes should place more emphasis on enhanced sensors to boot situation awareness. Large long-range weapons should be carried to engage enemy aircraft before detection.
Thus small and agile fighters will be less useful in future combat as they lack the size to carry sensors and weapons.