I worked at company that architected their multi-tenancy in almost exactly this style. In their particular case, only a few of the very largest customers had th

I worked at company that architected their multi-tenancy in almost exactly this style. In their particular case, only a few of the very largest customers had their database set aside on their own dedicated instance, but every customer did have their own DB with their own set of tables. Having worked in that world (every customer had their own DB) and on a product where all customers had their data intermingled in one gigantic set of tables in one giant DB on one logical instance, I'd definitely encourage the "every customer gets their own DB". Giving every customer their own table means you're going to need database administrators. For these folks their dedicated job was maintaining, operating, and changing their fleet of databases, but they where very technical and were amazing to work with.