I don't think this case is representative (for a bunch of reasons, trying to avoid being overtly political, but including that CA is the most powerful state even without a senate delegation, and Boxer is fairly senior on her own.)
I did not intend to give the impression that I thought that her seniority was a reason to keep her around. It was more of a half-assed lazy web request. In the interim I put a question on the politics SX and emailed an old professor. I do agree that it will not be as big of a loss for CA as it might be for other states, e.g. VT losing Leahy.
Not avoiding being overtly political: In my opinion the House is similar to the kids table at a big thanksgiving dinner. Representatives and children are Every now and then the kids get too rambunctious and noisy and the adults (i.e. the senate) have to step in and tell the little brats to behave. If I could choose any elected office I would pick being a senator. The House "is teh suk."
Also, California and other large states can't get much impact from federal pork because they have to spread it too thin across a large population.
Wyoming and Alaska can get a few billion dollars in waste and abuse money from senior senators and spread it across half a million people. That makes for a lot of fun for anyone who's in on the windfall of bridges to nowhere, local culture grants, "national security" slush funds, and the like.