I Agree adsense is sliding down hill, I think its why a search on G ads cover 90% of the page they need to keep up the income.
I do agree ads don't match page, i didn't notice you now could turn on or off user-interest ads in your account. have you tried kontera or chitika might be worth testing. I had a low day because I turned off user-interest based ads but what happens is you lower the bidding for your site, so you get less PPC. My CTR went up, but CPC down.