Adsense is scary, while it can provide a website with revenue it can also cause the pages of that website to look spammy depending on placement and theme. Besides impacting the appearance of a page adsense might also be the catalyst for manual action which affect serps.
It doesn't have to be that way.
I'd like to see Google develop a tool where adsense units can be disabled remotely, on a unit by unit basis, if a human evaluator deems a site isn't measuring up well with recommended standards. I believe that adsense should never be the cause that makes a human evaluator take manual action on a website.
I'd much rather have a single, or multiple, ad units disabled over losing search engine positioning if given the choice. When a site suffers manual actions, especially to a limited number of pages or against a particular keyword, the webmaster is not always informed and continues to work on a site that cannot accomplish what he/she is working hard to attain.
Google human evaluators need to be able to disable ad units, on a unit by unit basis, so that adsense isn't ever the cause of a penalty. Then maybe adsense wouldn't be as scary when you try to listen to the "you're not using your max available units" emails from adsense.