With Apple (NASDAQ:AAPL) shares still trading mostly sideways following the January earnings plunge, investors continue to search for the next important catalyst that can help the company return to its former glory.

The usual suspects are all here. New iPad models could come as early as next month, but may also be pushed out to later this year, because the tablets were updated at the end of 2012. The next iPhone is potentially due out this summer, as Apple may be moving that product cycle up to fend off competitors. The inevitable dividend boost, or some other form of capital return, is very likely imminent, because it's that time of year.

However, there's likely another underappreciated catalyst on the horizon that most investors aren't considering: iOS 7.

Lucky number 7
Apple hosts its Worldwide Developer, or WWDC, in June. That's less than three months away, and the company should expectedly preview the next major version of its mobile operating system platform iOS. Arguably, this year's iOS 7 release may prove to be one of the most important versions for Apple's ecosystem in years. There's one specific reason why this version will be so critical: Jony Ive.

Late last year, Apple ousted former iOS chief Scott Forstall amid a rare executive shakeup at the highest echelons of the largest tech company. Forstall is the man who led iOS to become Apple's dominant platform over the years, and it now powers over 70% of revenue. He's also the executive who's been widely criticized about Apple's interface design direction. I'm not just referring to the skeuomorphism, but, rather, the overall interface.

Over the years, critics have continued to deride the iOS interface as dated, since the platform still looks mostly the same as when the original iPhone launched in 2007. There have been numerous changes over the years, but the core interface is largely unchanged. The toughest part for Apple investors? The critics are absolutely right.

Goodbye, first mover advantage
(NASDAQ:GOOGL) has come an incredibly long way with interface since the early days of Android. Hiring Matias Duarte out of Palm before that company was swallowed by Hewlett-Packard was a big part of that, since he brought many innovative new interface designs to the platform. In characteristic Google fashion, the search giant experimented with numerous ideas with Android interface before getting to the clean look it now sports.

Microsoft's (NASDAQ:MSFT) Windows Phone interface has been widely hailed as featuring an innovative interface, even if that hasn't translated into meaningful market share gains. The live tile approach is wildly different than both iOS and Android, for better or for worse.

BlackBerry (NYSE:BB) is also exploring many new interface ideas with its new BlackBerry 10 platform. CEO Thorsten Heins even recently had some fighting words, calling the user interface five-years old (it's actually six).

Apple was undeniably the first mover in capacitive touchscreen interfaces on smartphones, but it has been slow to embrace change as rivals continue to dream up new interfaces that now feel more modern compared to iOS.

Ive's our man; if he can't do it, no one can
Ive is now the head of all "Human Interface," along with his normal duties as industrial design guru. He's traditionally been a hardware player, physically crafting the minimalist designs for Apple products; but now investors will see him give software interface a shot. He'll still have Craig Federighi's engineers doing the nitty gritty work for him, but Ive will now call the shots with the overall look and feel of both iOS and OS X.

Shortly after the shakeup, an anonymous Apple designer told The New York Times: "You can be sure that the next generation of iOS and OS X will have Jony’s industrial design aesthetic all over them. Clean edges, flat surfaces will likely replace the textures that are all over the place right now." There's no shortage of third-party concept videos floating around out there as loyalists contemplate what iOS 7 will look like under Ive's direction.

An iOS interface design makeover is long overdue, and Ive is just the man to deliver it. Software experiences are one of the most critical aspects of any device, and a revamped interface could translate into a meaningful boost in demand. A dramatically improved interface could spark a whole new wave of upgrades, as well as lure new users into the platform.

An Ive-designed iOS 7 could be a total game changer.