MG Siegler:

The problem is that all of these different devices require testing for each and every app. They all create a different Android experiences — some in subtle ways, some in big ways. Some run certain Android apps, others don’t. Some apps work fine on one device then are buggy as hell on another one. Sometimes this gets fixed, sometimes it doesn’t. It depends on the popularity of that device and the resources the development team has.

Yes, that’s a problem.