Samsung's (NASDAQOTH:SSNLF) next flagship smartphone, the Galaxy S6, is shaping up to be an impressive device, one fully capable of challenging Apple's (NASDAQ:AAPL) iPhone 6.

Yet, one of its most attractive features could prove disappointing.

According to Bloomberg, Samsung plans to release two versions of the handset -- only one of which will offer a curved display. While it may make sense from a pricing standpoint, splintering the Galaxy S6 line could prove to be a major mistake.

Samsung needs something new
In recent quarters, Samsung's handset sales and profits have tumbled, as demand for its high-end, high-margin Galaxy handsets has proved disappointing. Given the iPhone 6 and iPhone 6 Plus' strong reception, it appears that much of Samsung's recent success was predicated on its monopoly-like control of the large-screen smartphone market.

With Apple having finally caught up, Samsung needs a new selling point for its Galaxy handsets.

Late last year, Samsung unveiled the Galaxy Note Edge, the first (and only) smartphone with a display that wrapped around the side. Although it was a fully functioning device, it appeared to be more of a prototype product than anything else -- it was released in limited quantities, and enjoyed little marketing support. But it could be time for Samsung to truly push its new display technology into the mainstream.

Bloomberg believes that one version of the Galaxy S6 will come with a screen that wraps around both sides. If it's sold in large quantities, and benefits from Samsung's massive marketing budget, it will be the first and (until another company copies it) only mainstream phone with a multi-sided display.

Support for the S-Pen has been low
Regardless of their operating system or manufacturer preferences, consumers that want a curved display will have to buy Samsung's handset -- similar to the way in which consumers looking for larger phones turned to Samsung's devices in the past.

The appeal seems obvious -- the two side displays could greatly enhance productivity. Apps could include taskbars; games could use the edges for enhanced control.

But in order to take advantage of the extra displays, developers will have to go through the extra work of updating their apps to support Samsung's unique hardware. That process may not be worth it if the curved Galaxy S6 moves only a modest number of units.

Samsung's S-Pen -- its smart stylus -- has received little developer support. The S-Pen is included with every Galaxy Note product (both handsets and tablets), but developers haven't taken advantage of it. To be fair, there are a few drawing-focused apps designed with the S-Pen in mind, but the overwhelming majority of Android apps don't support it -- probably because it isn't worth their time. Although Samsung has sold millions of Note devices, they still represent a tiny minority of Android devices.

Will it be popular enough to matter?
The inclusion of larger displays on Samsung's prior phones required no developer support -- apps benefited from the extra screen real estate regardless. Websites and digital books became easier to read. Videos became more pleasant to watch. Curved edges could prove just as revolutionary, if not more so, and spark a resurgence in the demand for Samsung's handsets. But that will only happen if mobile developers are willing to take advantage of Samsung's unique hardware.

By splitting the Galaxy S6 line into two -- one curved, one not -- Samsung could dramatically lower the chance of that occurring. Galaxy S6 owners were already going to be in the minority; curved Galaxy S6 owners will represent an even tinier fraction of the Android base.

Under that scenario it seems unlikely that many Android developers -- except Samsung itself -- will bother taking advantage of the edge display. If that happens, the Galaxy S6's edges could become a useless gimmick rather than the next must-have feature.

Sam Mattera has no position in any stocks mentioned. The Motley Fool recommends Apple. The Motley Fool owns shares of Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.