What I've noticed is this: In the past couple seasons, two good robots could hold up an alliance and win a match. The third one could play some very effective D (and some finals matches have been decided by how good the third robot is at playing defense) but especially in the quarters and semis the overall firepower of the top two robots in the top two alliances is too much for the others.
This perhaps is a side effect of
FIRST's decision to design really offense-oriented games since 2007. That year was crazy: an alliance could score 256 points in one match and 0 the next, all depending on how much defense was played against them. Rack 'n Roll was, in my opinion, the only game where three good robots could beat two great robots and one not so great robot, which resulted in a lot of 8 over 1 upsets. This phenomenon was augmented by the fact that since defense could shut down many offensive teams, the best teams often would not seed first. Even when they did, they often lost if the regional or division was stacked enough to provide power to the #8 alliance.
Look at the TBA results for GLR and West Michigan... more wins for blue than red in the elims. Oh look... 1114 and 67 lost in the semis due to amazing defense and the fact that 57's robot could not provide the defense necessary to stop the opponents from scoring. In 2007, none of the #1 alliances at Champs escaped the divisions and reached Einstein. The
#8 alliance of 190, 987, and 177 won in the finals. This could be interpreted as proving my point that 2007 was the only recent year where the #8 alliance could be the best alliance at an event.
However, back then there was this huge discussion about how overpowered defense was in FIRST and how boring it was to watch robots bump into each other instead of score. There were also instances where teams played defense that was
too rough and complaints about how the serpentine draft gives an advantage to the #8 alliance and should be done away with. Perhaps as a result, FIRST has designed games in recent years to be based on offense, so the good teams can seed high in qualifications and be less hindered by defense in the elims. These offense-powered games in recent years have given the #1 alliance more of a chance to dominate a competition.