I think it would be advantageous to update your CMS so that title tags and meta descriptions are not identical across blog listing, topic listing, author listing pages. This is something we do with our Wordpress CMS builds so as to at the VERY LEAST include the name of the "Topic"(or taxonomy as they would be referred to in Wordpress) into the title tag of a taxonomy listing page. Therein making each individual topic listing page unique.
I'm confused as to why Hubspot thought it was best practice to give these dynamically generated listing pages all the same exact Meta info?
But, as you identified, this is not possible within the current HubSpot blogging tool. This is probably because it is not a critical feature of providing a blogging platform from which SMEs can easily drive big benefits. But I bet it will come.
Phil, looking at this topic myself and HubSpot still hasnt addressed this issue. Didn't know if that link you provided was your own or not. It's no longer available so thought I'd ask.