For our team, we actually ruled out the extended drop down intake/bridge arm because we thought it would be best to simplify our rookie bot a bit, but it was in our initial design.
We later ended up adding these features anyway
Overall I think it just comes from experience and a good design process. Also, collaboration with others helps A LOT.
Also a lot of the time there are normal teams who will come up with something like drop down intakes whathaveyou, but don't execute them as well as the elites.
I think for this season, the real feature that put a couple teams at the top was a balancing aid + drop down intake.