A 3rd-4th place at DreamHack Dallas is pretty good too. They also had another Bo3 win against Vitality, and a Bo3 win against North, who were ranked #9 at the time. The whole top 10 was very weak because of stuff like Na'vi skipping events and FaZe replacing players. Also, them losing to tier 3 NA teams wasn't that big of a deal considering that they beat those NA teams 22 times.
Obviously BLAST Moscow and the DreamHack Open stops are tier2/3 event, but AVANGAR had 2 good results in a row, which mean that there was at least some consistency to the team.
AVANGAR should have been #5 max, and FURIA shouldn't have ever been in the top 5, but there is some reasoning behind the rankings. A lot of this can be attributed to Na'vi skipping events and EG's weak result in the time periods.