Apple's (NASDAQ:AAPL) iPhone lacks a number of hardware features common to most expensive Android handsets. You won't find an Apple-made handset with NFC technology, nor can you purchase an iPhone with a screen size remotely comparable to those offered by Google's (NASDAQ:GOOGL) hardware partners.

Now, another feature can be added to the list: Both Sony (NYSE:SONY) and Samsung (NASDAQOTH: SSNLF) have embraced waterproofing, offering flagship phones that can survive a dip in the pool.

Apple closing the gap
While Samsung is often criticized for copying the iPhone, Apple has added a fair number of features to its smartphone that were originally embraced by Google's hardware partners. Samsung, for example, offered 4G LTE on its second Galaxy S handset -- Apple didn't bother with the feature until the iPhone 5.

Samsung was first to popularize the concept of a larger screen, originally with its Galaxy Note phablet, and later with its own flagships. Google's other hardware partners, including Sony, quickly followed.

Apple still lacks a larger iPhone, but that should change relatively soon. Apple's CEO, Tim Cook, has never ruled out the idea of a larger iPhone, and numerous reputable media outlets have reported that the iPhone 6, when it ships later this year, will sport a larger screen.

That could put Google's hardware partners in a tricky spot -- while there are many factors that may have influenced consumers to chose an Android phone over Apple's iPhone, the bigger screen has been, over the past few years, a major defining characteristic. If Apple were to finally follow Samsung and Sony in offering a larger iPhone, it could capture some of Google's users.

Is waterproofing the new must-have feature?
But Samsung and Sony seemed to have moved on to the next thing -- in this case, waterproofing. Sony struck first: the original Xperia Z, released last year, can survive underwater at a depth of up to 1 meter.

Samsung followed suit, releasing a special variant of the Galaxy S4 (known as the S4 Active) that was likewise waterproof. However, the S4 Active was a limited release, restricted to a few carriers (AT&T in the U.S.).

This year, Samsung has made waterproofing a focus: All flagship S5s will have the feature. Sony, likewise, remains wed to waterproofing -- like the original Xperia Z, the Xperia Z2 can survive water submersion.

There are, of course, some trade-offs: To make the phone waterproof, all of its ports must be covered. A number of tech critics have found the necessity annoying: Business Insider's Steve Kovach, reviewing Sony's Xperia Z, wrote:

But because the Xperia Z is water resistant, you'll have to put up with some compromises with the design. Every port and opening is covered with a tiny hatch that you have to pry open with your fingernail whenever you want to access the headphone jack, USB charger, or SD card slot. The hatches may keep water out, but they also keep you from quickly getting to the ports. And when they're open, each hatch hangs from a flimsy plastic thread, which is distracting and ugly.

PCWorld also found the port covers annoying, but ultimately concluded that users could live with them.

The advantages of fragmentation
Despite the trade-offs, some iPhone owners are calling for Apple to make a waterproof smartphone: TechCrunch's Matt Burns recently urged Cupertino to follow the trend. Will Apple do so? Maybe, but if the company's recent history is any example, probably not anytime soon.

I can't say for certain if waterproofing will emerge as the next great smartphone trend. While some users may consider waterproofing a must-have feature, others (like me) could probably not care less.

It does, however, highlight the advantage of Android's fragmentation -- a situation that has largely been characterized as a negative for Google. While it definitely has its drawbacks, making software development more difficult, it also has its advantages. In this case, hardware innovation. While Sony and Samsung compete with Apple, they also compete with each other. To differentiate their products, they must be willing to experiment with the design.

Ultimately, that leads to features -- like larger screens and waterproofing -- that set their devices apart, and win consumers over.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.