There a definite gap between the experiences, but use cases are usually a bit different, too. Mobile devices are mostly used to check something up quickly on-the-fly as on PC you also do more planning ahead. So a scaled down experience is not necessarily a bad thing on mobile as that eases the pain of having a small screen, slow text input and possibly moving around in a noisy environment. Scaling down the features also forces the development team to focus on the essentials, which is not a bad thing even on PC.
Then again, it would be nice to get Slashdot css working on small screens, too.