Those saying that small devs or PC only developers (CD Projekt for example) will suffer need to remember that they generally don't release games with DRM (Humble Bundles anyone?), which means that they could always be sold second hand anyway. This ruling/law will only really affect the bigger publishers. Obviously the effect it will have could be debated to the ends of the earth, but I think that the issue is far too complex to make sweeping statements as many have. Try it and see perhaps...
I do think it will push more companies towards the F2P model, but then again, with all the DLC and "Elite/Premium" services, they were going that way anyway. The few remaining big single player games will be those it's most likely to strongly effect, and it'll be interesting to see how it pans out. As I said before though, The Witcher doesn't have DRM and can be resold, but CDPR have done pretty well out of it and the Xbox version, which can also be resold.