Design: evolution, not revolution?
The Galaxy S III was a radical departure from its ancestors with its pebble-influenced, Hyperglazed body. Samsung may keep its cards close to the vest this time around: if Chinese leaks are showing more than just a clever disguise, the Galaxy S IV will preserve much of the design language from both its ancestor and the Galaxy Note II. The new body would mostly add a touch of refinement through metallic trim and, just possibly, a slightly larger 5-inch, 1080p display. Most of the plastic would also remain, though, so there may be disappointment in store for those who want HTC One-style construction.
Samsung hasn't offered much in the way of its own clues. While it did post a cryptic image that would loosely match what we've seen, the shadowy picture also omits basic elements like a speaker. It's either an abstracted representation of the GS4, or isn't connected to any real product.
Performance: what you're really here for
However much the GS4 changes on the outside, the real star may be the inside. More than one rumor, including difficult-to-verify benchmarks, have alluded to an Exynos 5410 processor that many interpret as a variant of the Exynos 5 Octa unveiled back at CES. If that's what's inside at least some GS4 models, the phone will represent a significant leap over Samsung's 2012 technology. The Exynos 5 Octa isn't a true eight-core processor -- but it does have a more powerful quartet of ARM Cortex-A15 cores that could trump the Exynos 4's Cortex-A9 underpinnings, as well as another four Cortex-A7 cores that can kick in to save power. Samsung further claims a large stride forward in 3D graphics, which haven't changed much in the company's processors (save for the Exynos 5 Dual) since the Mali-400 from the Galaxy S II.
There's no guarantee that everyone will see a similar speed kick. Outlets such as Bloomberg claim that the American GS4 variant may run with one of Qualcomm's quad-core chips, such as the Snapdragon 600, paralleling a decision to use a dual-core Snapdragon S4 in the US-based GS3 instead of the international model's Exynos 4 Quad. While the 600 is certainly one of the faster mobile processors available today, we have yet to see a direct comparison with Samsung's silicon.
Other hardware upgrades could be more consistent. Most specification rumors have the GS4 carrying 2GB of RAM from the start, rather than the 1GB that appeared in some early GS3 models. It might also stuff in a higher-resolution 13-megapixel rear camera. These upgrades wouldn't put Samsung's device significantly ahead of the pack by themselves -- 2012-era phones like LG's Optimus G got there first -- but they'd help the GS4 stay competitive.
Software: let your eyes do the work
Samsung made much ado of Smart Stay for the GS3: when active, the phone could automatically keep the screen awake as long as it could see your face. The GS4 might make that hands-free intervention a centerpiece of its software. Both a New York Times assertion and purported screen captures suggest that the new phone could include Smart Scroll, an optional feature that would scroll pages as your eyes reach the end of the screen, as well as Smart Pause, which would halt videos when you're distracted away from the display.
Just don't expect much else. The same apparent leaks also show a modest upgrade to Android 4.2, without many conspicuous changes to the TouchWiz interface beyond what we saw in the Android 4.1 upgrade. Not that customers will necessarily complain if there's nothing conspicuously new -- when Samsung has been selling GS3 units in the tens of millions, it's evident that many see its existing UI as good enough for now.
Launch timing: is the US the new star?
The GS3's launch reflected Samsung's awareness that the US was becoming the main battleground for smartphone market share: after years of unveiling phones for Asia and Europe that didn't reach the US until months later, its 2012 flagship was on most major US carriers within weeks of a London unveiling. Clearly, that much-improved timing paid off with greater influence. A decision to hold the GS4 launch in New York City shows just how much the GS3's American success has changed Samsung's worldview -- the company was quick to admit that it chose the GS4's introduction venue following demands from US carriers.
Does that translate to a quick US release? At this stage, that's the least certain detail of all. We've heard virtually nothing reliable about ship dates or carrier choices. Logic would have a US-centric media event dictate a US-centric schedule, but there are no guarantees that Americans will be walking out of stores with the new Galaxy before their counterparts in London or Seoul. Nonetheless, it's doubtful that Samsung will revert to the bad old days of cavernous gaps between press events and in-store availability. The GS4 will be the company's most important phone, debuting in what's arguably the company's most important market, and we'd expect relatively close timing to match.