I'm sorry. I presently have no advice to give, except for you to try different things. What was working once before is obviously not working now.
I suggest you look at the Hubpages ad layout/format and see where the ads are now showing up. It might give you an opportunity to notice where the ads are showing up on your hubs. It would take careful analysis of each hub, so you can gauge where exactly the ads show up with regards to your writing in each hub.
At least that is what I've done. Example: If you take a look at my celebrity hubs, you will notice a HUGE change in location for Google's main block ad. I no longer have it at the top of the page, simply because there is already a HUGE ad block on the right side frame. So I have moved it down into the hub. Seriously, check out any of them, I moved it in all of them. That is what I mean about testing for yourself.
I made some changes and have seen an increase in clicks, just like I had before the Google slap. However, the revenue hasn't increased, so that hasn't made much of a difference. But, hubs are getting clicks that were not getting clicks before, so to me that is a bonus. That is why it is important to be more accurate with keywords/tags, because that is what controls your ads, as well as the content.
I've place pictures on my poem hubs, which were not there beforehand. It did that because I wanted to test a theory about moving the Google Block ad away from the SIDE Block ad in the right frame.
So, that's the best I can say. It's not advice, but it is what I have done.