first of all very good analysis but:
In addition to being intimidated, having a salamence covers the entire team very well since with a little wear Draco Meteor can kill practically any Pokemon that bothers the Garchomp sweep. and its a more aggressive option
i like use rotom or tyranitar for to cover climates but I use a lot more to tyranitar i wouldn't call it filler because it is very important to avoid a sweep from some sun, rain etc