It's not a completely different beast, is it? It's basically like a regular flu or severe cold, and yes rhinovirus can be deadly to the elderly, it's just nobody normally notices or cares because rhinovirus isn't "new". If anything it's actually less bad than flu because flu kills children too and this one doesn't.
Nonetheless, the original SARS-1 (which is way closer to SARS-2 than say OC43), is known to be causing long term, debilitating health complication among significant number of survivors
And yet it didn't turn into a worldwide outbreak, so one must ask how much value this classification scheme actually has, given that SARS-2 is really nothing like SARS-1 in either infectiousness nor severity.