Unlike the new DSC-RX100 Mark II, Sony's new DSC-RX1r doesn't rock the boat with too many new features.
In fact, it's almost exactly the same as the DSC-RX1, save for one minor detail: the anti-aliasing (AA) filter has been removed. Sony isn't the first company to make such a move: in recent months, we've seen Nikon introduce the D800e and D7100, and Pentax has produce the K-5IIs, all of which come without AA filters (not to mention a few mirrorless models).
There is some downside to removing the AA filter, as the DSC-RX1r becomes more susceptible to moire, certain interference pattens that can show in materials with small repeating patterns such as fabrics, screens, and other grids. Neocamera has an excellent example of what removing the AA filter can do for the Pentax K-5II/K-5IIs.
For all practical purposes, unless you consistently take photographs of moire-susceptible patterns, going without a AA filter will likely improve the perceived sharpness of your images by an appreciable extent.
How well it works in practice will have to wait until we get a review unit in hand, but based on the performance we've seen in other cameras, the RX1r is probably a smart move on Sony's part, as it takes an already-sharp camera/lens combination and makes it another tick sharper.
In all other respects, the DSC-RX1r is the same camera as the DSC-RX1. Same full-frame sensor (still hard to believe you'll find one in a camera this small), same stunning, fixed, 35mm Zeiss lens.
Sony is trying to up the cred of the DSC-RX1r and DSC-RX1 as more than just street photography tools, offering a full series of accessories for the models, including the same (in our opinion, a bit overpriced) EVF and OVF from before, as well as a series of filters and adapters, the stereo microphone we mentioned in the DSC-RX100M2 article (though largely unnecessary as the RX1 features aux mic inputs), bags, body wraps, compatibility with the USB tethered remote, and more.
Much like the DSC-RX100 and DSC-RX100M2, Sony will continue to sell the DSC-RX1 even as the DSC-RX1r is introduced. The good news is that since the RX1r is virtually identical - save for the lack of an AA filter - there will be no price increase. The bad news is that it means there will be no price decrease for the original RX1. That means that both cameras will be sold for the foreseeable future with an MSRP of $2799.99.
The new RX1r will be available starting in mid-July.