I know this will seem like I want to return to the old sub-sites hierarchical model, but we do still have users who pay attention to their browser address bar when they are trying to understand how a page fits into the overall structure of an intranet or portal.
While Hub site navigation (sort of) allows us to visually reflect the relationship of a site to its 'parent' hub, there's nothing in site collection addresses that provide this visual cue.

I say 'sort of', because when you are on a site that is related to a hub, there is no state change to the hub navigation link for the 'active' site.

We still have many users who rely on these types of visual cues to help them understand the context of the content they are consuming and where else they might go on a site if they haven't found what they are looking for. Related to this is the absence of breadcrumbs (out of the box) which really annoys me.

These things are also conventional design patterns that have been in place for 20 plus years. My gut tells me we should not be throwing these away so lightly.

I recognise my request may be a bit tricky to achieve in the multi-site collection approach, but I live by the philopsophy of 'If you don't ask, you don't get'