I will say this about the asteroid plot:
I too reacted with dismay when I saw the promo. However, at the moment we don't know what the real story is. Remember that we've had a few asteroid scares in the past few years, in which a new asteroid was discovered and its orbit plotted, and the orbit seemed to indicate that it would intersect with Earth in the future. (The one I recall most recently was Asteroid 2003 QQ47, which they thought would hit Earth on March 21, 2014.)
If that's all the plot line is -- they track an asteroid, think it will hit Earth in the future, then discover that they're wrong, I wil be fine with it.
And why, you may ask? Because honestly, I don't think our government is going enough to track Near Earth Asteroids. We have a program in place to track such things so we can spot them early enough to deflect them, and the program is WAY underfunded. People may laugh, but statistically speaking, an asteroid has a close to 100% chance of hitting the Earth within the next million years. If we care at all about keeping the human race alive, we need to start thinking in the real long term.
I'm so serious about this that I have occasionally written to my elected officials about this.
So if WEST WING goes the above route, it'll just be another one of the episodes in which they bring up a pet issue, like they did with the geographers who wanted to convince the government to stop using the Mercator projection.
On the other hand, if the story involves an asteroid that will be hitting Earth tomorrow, and they're all screaming "We're all gonna die!" then I might concede that WEST WING has jumped the shark.