edit: My conclusion, ignore any running form purists or blow hards. Throw some shoes on. Go run. Conservatively and following the laws of training. If you get hurt you can fix it and it usually doesn't suck (stretching, less running for a while, strength training). If you don't get hurt, you were better off not overthinking it :)
https://www.ncbi.nlm.nih.gov/pubmed/26126256
http://www.kinetic-revolution.com/dont-believe-the-heel-stri...
Also: Changing gait is very hard: https://runblogger.com/2011/11/just-quick-post-to-announce-t... -- people revert when they get tired unless it is very deeply ingrained as a change.
edit: My conclusion, ignore any running form purists or blow hards. Throw some shoes on. Go run. Conservatively and following the laws of training. If you get hurt you can fix it and it usually doesn't suck (stretching, less running for a while, strength training). If you don't get hurt, you were better off not overthinking it :)