The most obvious is they simply get in the way -- they are a frustration. In the same way that you just nod and tell the airport check-in attendant you don't have a gun and you packed the bags yourself, every time you go to a Web site on a new browser, you just have to go through the routine of clicking "okay, i get it." The wording may change, but the annoyance remains.
So there are a few people who are not receptive to the EU looking at this again, but to me, it sounds like common sense. Allow people to pre-set a preference for a browser and that can be conveyed to each site they visit. Presumably the industry's concern is that if there is an option to refuse all cookies, or at least third-party cookies, then ad revenue models will begin to look a little shaky.
The truth is that people are increasingly being tracked online by the services they remain logged in to -- Facebook and Google are obvious IDs most of us are not aware we are using when we surf the net.
More to the point, the cookie is being widely seen as yesterday's technology. It's still useful today -- don't get me wrong, of course it is. However, we have reached a tipping point of being mobile-first and, of course, in the world of mobile, there are no cookies.
Instead, marketers need to recognise a person by their device or perhaps the services they are logged in to. If you consider how long it takes for EU talk to turn into an agreed-upon new law, then you can imagine how far down the mobile-first road we will be by the time a browser-based cookie preference system might be in place.
So to be completely honest, it's a late move by the EU that I don't think anyone should be too annoyed by, should they? We're going to lose the annoying banners asking us to click "OK" or "accept" cookies at about the same time that the cookies themselves face redundancy.
It's a sensible move that will ultimately not be as detrimental to digital marketing as people currently fear.