Wouldn't it be nice if Google communicated to you, maybe in Google Search Console, if your site has been migrated to the mobile first index? Even more so, wouldn't it be nice for Google to tell you if your site is ready for the mobile first index or not and if not, what to do to make it ready? These both would be excellent tools in Google Search Console as webmasters and publishers are a bit nervous about what this might to do their rankings.
For example, if you continue to panic about the mobile first index, but you've already been migrated to it several months ago and you don't know it yet, for some reason. Why should you continue to panic about it if the migration was a success and your rankings did not change due to the switch. Why can't Google just give webmasters a heads up that they've been migrated and the webmaster can then make decisions based on that date of migration if things went smoothly or not or if they need to make some tweaks to their content, navigation, schema or other elements based on the migration?
And of course, if Google communicated such issues prior to the migration via a report that scores you on readiness for the mobile first index - that can both benefit Google in their desire to go forward with the mobile first index, as well as webmasters who deeply care about making sure their mobile versions are ready for it.
Google has provided tools for AMP validation, HTML issues, duplicate title tags, schema issues and much much more. But some webmasters feel they are blind with this mobile first index that is coming soon.
John Mueller of Google wants you to tell him why you want such tools so maybe he can use that to go back to the team to prioritize the development of it?
What action would you take from that? How would it be useful? Would love to hear people's thoughts!
— John ☆.o(≧▽≦)o.☆ (@JohnMu) November 8, 2017
Forum discussion at Twitter.