Re: Only 3 hours?
The SpaceX crew Dragon deliberately went on a slow journey so the systems and habitability could be properly tested, in fact after the first launch attempt was aborted for weather the next opportunity was skipped because the flight would have been too short. Future Dragons may well take a quicker route if the timings are right.
All launches to the ISS from whatever launch site are timed to go up as the ground track of the ISS orbit passes over the launch site, but the ISS can be at any point along the orbit. This means the station and craft land up in the same plane but have to wait until the Soyuz/Dragon/Cygnus/Whatever catches up before they can dock. The different rockets can cope with different amounts of off ideal timing by doing a small (it costs fuel and payload) dogleg manouevre, and the latitude of Baikanour means the ground track gives a lot more flexibility in exact launch times when combined with the Soyuz capabilities. The Russians are thus able to pick launch times and dates to minimise the flight time, NASA and JAXA could pick launch dates that would give a 2 orbit 3 hour trip, but that would drastically reduce the number of possible launch windows.