I read through the thread, I don't think anyone mentioned this but could they take around 10- E175's and base them into LAS? Fly them only to non-southwest markets on a 1x-3x daily basis. You would compete with Allegiant on a few routes but most of those are only 2x per week and don't cater to the business traveler. Examples might be Santa Barbra, Eugene, Medford, Fresno, Monterey, Redmond, other Montana and Washington cities seasonally.
Just trying to think outside the box where there is limited competition so don't kill me if you think it is a bad idea.
I don't think you have a bad idea at all. I do however doubt that AAG would be interested in fighting all the competition and crowding at Vegas., especially WN, G4 and even DL's focus operation there. I know it's a huge market but tends to be low-yielding and already has lots of service. They're already facing those issues at LAX.
Since AS just pulled their (inherited) nonstop to JFK, and the nonstop service to ANC is gone, that would also indicate their intent to keep LAS as a regular but well-served out-station from their hubs and focus cities. That situation could change in the future but for now, I don't think so.
That being said, I do expect that LAS will see service to AAG's growth points in California in the not-too-distant future. As part of growing their CA presence, AS needs to connect McCarran with at least SAN, SNA and SJC at a minimum, with maybe FAT, SMF & STS in the mix. It's certainly possible that some of the other w/c cities you mentioned could also see service to LAS at some point but I'm sure that would be down the list a ways. (BTW, I think PHX will see the same adds as LAS from AS one of these days.)
AS of course already serves LA and SFO from Vegas, and LAS-PAE should start sometime soon. Beyond that, I think AS will be happy to let WN and G4 serve the rest of the world from Vegas.