Google is going to implement an improvement to the top ad placement formula at the end of August.

Currently Google looks at a multiplication of the quality score and the actual cost per click.
Google will carry on weighing the quality, BUT: the actual cost per click will be exchanged to the maximum cost per click.
Why is this?
The actual cost per click depends too much on other advertisers. There can be really good ads with a great quality score but they will not automatically appear in the top positions when they bid less than other advertisers.
The new formula will give you more control over the ad-ranking, but you might also end up paying the maximum cost per click you chose.

So therefore the new ad-rank will penalise 'quality' ads by charging more.

As an advertiser, what do you expect to happen to the CPC's and volumes?

I can think of a few consequences:
-that it will be more difficult to bid at the top positions due to more advertisers trying to improve their rank by higher maximum CPCs
- that advertisers with smaller budgets will have to invest more in high quality ads
- that in general some quality will get lost as it will be easier now to appear on top for more money
- users will probably start to click more on lower rankings, expecting more quality