Modern search may add ML based features etc., but the control that we had in classic search is what made it the enterprise search. Many of my customers have been asking about customizing the modern search. Announcements of new features at #ignite2019, although not yet available, is welcoming. Check this blog post. I would like to call out 2 sections that should help ease some of the concerns that I have heard from my customers:
“Later this year we will also deliver capabilities to set up custom verticals, add your own refiners, and use adaptive cards to create your own visualizations”
“we are bringing in capabilities so that you may redirect the suite bar search box to a page of your choosing”