If you want to update (insert changes) all existing sites in a SharePoint 2013 web site, which one is the best option to start with? creating all sites based on Site Definitions or based on Web Templates? what has been changed in SharePoint 2013? thanks for your advice.
If you want to update a bunch of sites, regardless of the SharePoint version, I would suggest the following (regardless of the original creation method, be it a site definition / web definition)
So in short, I would turn your question in the opposite site, regardless of the site creation method, which option will chose to do the required updates ?