I’d like to +1 keeping “highway=track”. In my area, these are vehicle-capable roads, with legit street signs and names. I’ve run some that were (or turned into) agricultural dirt tracks, but there are tons of those with no name so there must be something special about those that have one 
. One of the main attractions of the CS challenge for me is to see ALL of the city, for me that also includes the more rural parts of town. They also tend to make for pleasant running, though I appreciate that that isn’t the main consideration here. I’m probably a bit biased since I’ve bagged quite a lot of them by now, the recent update to my city which brought tracks back had my street count jump by around 100 streets.
That said, I agree with Jordi from the Frustrated with CityStrides thread: a stable query would be ideal. I remember when I first joined CS the map had all sorts of stuff, including restaurants, bus stops, statues, and random buildings as “streets”, since then the query has been fine-tuned and stripped of the obvious “non-street” stuff to the extent that I’m happy with the status quo.