Never played it

I've never actually played the game.  So, I can't comment on it being unplayable.

The pathing for traffic may be fairly stupid, but it's not necessarily all poor programming either.  If each driver is really running its own A.I. then they might be trying to keep the processing power to a minimum.  Sure it doesn't entirely forgive taking the most direct route, but it may explain why so many cars drive to the closest available house and then the next and so on.  I mean from the driver's perspective they only know where an available house is before the set out on their trip.  If it gets sold while they're on the way they'd only know if they're using their phone while driving.  That's just not a good example.