What I mean by "gatekeeper" list, is a list that you test your potential competitive builds against on your kitchen table. I ususally have one solid, easy to play build ready that any build I´m working on has to get through (in a solitaire match) to get a chance at the store.
Sometimes the "gatekeeper" build becomes the competitive build if it´s tough enough. Chewie/Leebo was a "gatekeeper" build of mine that simply beat all my more creative builds. I ended up using it in a local league and went 7-0 with it.
I guess Chewie is my "easy-mode" pilot because my current "gatekeeper" build includes good, old Chewie:
Chewbacca/Predator/C3PO/Luke/title/EU 60pts
Lothal Rebel/FCS/AutoBlasterTurr/Hera 40 pts