1. Not bait and switch. That would only be true if HA advertised aircraft A, knowing at the time that it would operate the flight with aircraft B. Unless you have solid proof of that, I'd drop it.
2. Reason for aircraft stuck in LAS could be all kinds of things having nothing to do with WX (or particularly WX at LAS). Could be MX, could be crew timed out due to prior delays and so on.
3. Unlikely HA will do anything. Not just the COC which makes this clear, but the reality of air travel these days is that w. capacity cuts, there's simply fewer aircraft out there and when the scheduled bird is out-of-position, the choices become cancellation or subbing a less tasty bird.
HA may throw a few miles OP's way as a CS gesture, but that would likely be it. More likely zippo if OP uses the "bait & switch" language or goes beyond voicing disappointment that he didn't get what he likes most.