I'm in agreement here. Don't see an urgent need on the coast, but Roseburg or Sutherlin is desperately needed, not only for shorter range vehicles, but also to provide density and better spacing. Grants Pass has been filling up at times, so I suppose they could expand that location, but... it's not the greatest location (imo), and making a new one (in Roseburg or Sutherlin) that provides more options and better spacing would be better than merely expanding GP.I agree that Springfield to Grants Pass could use another Supercharger Station in the middle — I could make it in my car, with much lower range (178 RM) and much lower efficiency than your SR+, but it isn't easy. Range anxiety in an SR+? That's a surprise. Maybe in winter with really poor weather, I suppose.
However, Bandon to Lincoln City is really easy, in part because the speeds on the coast highway are lower than typical I-5 speeds, so the distance doesn't matter as much, due to the reduced drag that greatly increases efficiency. Even Eugene to Florence and back is really easy for an SR+, so if you wanted to get to the coast and back home without charging it would depend on how far north or south from Florence you wanted to go. A loop of Eugene to Florence to Newport to Corvallis to Eugene would be easy in my car and trivial in an SR+. Even an out-and-back from Eugene to Coos Bay would be doable in my car and easy in an SR+.
With so many parts of the country under-served by Superchargers, your area is already relatively well covered IMO.
I drive a relatively long range car (310 Rated Miles), but I can't really avoid stopping in GP when heading south, especially in winter. The only ways to do it involve charging to near full in Springfield and driving slowly, both of which slow me down. It's annoying to have to slow charge with a >50% SOC and to have to stop at every supercharger, so better spacing opportunities are important when increasing density. I suppose you could make the same argument for the coast, but the difference is, most people are going to the Oregon Coast as a destination rather than blasting down the coast all at once on the same drive. Along I-5, you have a lot of Tesla owners from Vancouver, Seattle and Portland blasting straight through on their way to California (and vice versa of course).