In the Qualification Rounds ...
- if your robot can't do much of anything so your team plays defense then you're shooting yourself in the foot rank-wise.
- if your robot can score even one or two balls in a match, yet you decide to play defense, you are STILL shooting yourself in the foot.
- even if you lose the match it is to your advantage to score as much as possible in order to get a higher seeding score.
- high seeding scores cannot happen if you prevent the winning alliance from scoring alot of points, thus defense will equate to overall lower ranks should you focus on that in quals.
- the only "defense" should be you taking your opponents balls from their zone and scoring in your goals ... yet if the score differential is too high already then you might as well just score for your opponents anyways.
Thus, a team who's offensive capability is mediocre compared to its defensive capability should focus solely on offense during qualifications and save the defense for eliminations. Ergo designing explicitly for defense implies that you expect your robot's capabilities will be attractive enough to a high-ranked team to be picked; the reality is that those alliance selections are quite unpredictable, especially early in the build season.
Edit -- that does not mean robots should stay away from mid-field defense during quals, since your 'bot jockeys for position in order to feed balls from one side to the other... in elims mid-field will be
key since it is only there that balls return back to your offense after being scored. During quals it will simply be more important to keep the flow of balls moving than it will be to push the other robots around.