The iPhone may be one of the best-selling smartphones on the planet, but Apple co-founder Steve Wozniak believes Apple's flagship smartphone has fallen behind its competitors, namely those built by Samsung, when it comes to smartphone features.

Speaking at Businessweek's Best Brand Awards on Thursday evening, Wozniak said he was proud of how loyal Apple fans were to the iPhone, but also said "this loyalty is not given," shortly before denouncing his own company's smartphone.

"Currently we are, in my opinion, somewhat behind with features in the smartphone business," Wozniak said. "Others have caught up. Samsung is a big competitor. But precisely because they are currently making great products."

In the last two years, Samsung has effectively made its Galaxy S smartphone line into the flagship model for Google's Android OS, balancing slick design with forward-thinking user features. For example, unlike any iPhone built by Apple -- including the best-selling iPhone 4, iPhone 4S or iPhone 5 -- the Samsung Galaxy S3 can run two apps at the same time with a split-screen, prevent entering sleep mode by using its front-facing camera to detect the user's face, and the oft-advertised S-Beam feature, which allows two Samsung Galaxy S3 models to share files, photos and videos, simply by tapping them together.

The iPhone is a comparatively simpler smartphone: Users can organize and multitask across applications, execute various tasks with Siri, beam music and video to Bluetooth and Airplay-enabled devices, but besides those and a few interesting phone technologies, the iPhone is not a feature-ridden device. Most of the iPhone's power comes from within its ecosystem of easily downloadable applications, which make the iPhone into the versatile tool that it is.

That said, Wozniak is right: Apple has time and time again said "no" to most iPhone features we've heard rumored in the past, from NFC chips for S-Beam-like abilities, to advanced haptics that create molded buttons on the smartphone screen when an application calls for them. Apple has patented many of these features, meaning it has at least considered them at one point; yet, Apple would argue that simplicity and focus is what makes the iPhone so universally appealing.

However, Apple might spice things up over the next two years, with plenty of reports coming through the rumor mill this month saying Apple has plans to release three new iPhone models, including a true iPhone 5 successor (either iPhone "5S" or "6"), a cheap, plastic-made iPhone 5 (designed for emerging markets in Asia), and a large-screen iPhone+, originally reported as "iPhone Math."

Even if two of these rumored phones turn out to be bogus, Apple will most certainly release a true iPhone 5 successor in 2013. And Wozniak might actually like this one, considering how many new and noteworthy smartphone features this model may introduce.

We’ve heard several rumors about Apple’s iPhone 5 successor: For example, iLounge editor-in-chief Jeremy Horwitz released a lengthy report last month detailing the iPhone 6, noting an updated rear camera – “perhaps featuring Sony’s 13-megapixel sensor” – as well as a processor bump to an Apple-built A7 chip -- both the camera and flash enhancements, as well as the A7 processor, were mentioned in a similar report from KGI Securities analyst Ming-Chi Kuo, one of the very best in the business at predicting Apple's product pipeline.

While Horwitz may be accurate, one of the most rumored features we've heard about the iPhone 5 successor has to do with the signature home button, which is said to introduce an integrated fingerprint sensor to replace the need for usernames and passwords on the phone.

A fingerprint sensor makes great logical sense for an iPhone feature: Unlike other smartphones with multiple buttons at the bottom, the iPhone has only one mechanical button on its face, which makes it exceedingly easy and intuitive for users to find and use this feature. Furthermore, given Apple’s urgency to acquire Florida-based AuthenTec last July (as noted in the company’s own filing to the SEC), there’s an excellent chance that we’ll see this unique feature in a soon-to-be-released iPhone -- hopefully the iPhone 5S or 6.

We’ve also heard that Apple is investing a great deal of time, energy and money on the display for its next-gen iPhone 5S or 6.

A Jan. 3 report released by the China Times said Apple might switch to a "Touch On Display" panel currently in development at Taiwan-based Innolux Corp., which has reportedly been licensed to use Sharp's proprietary IGZO display technology.

Whether or not Apple chooses Innolux to make the next iPhone's screens, however, Apple is most likely going to feature Sharp's ultra-thin IGZO display technology in its next iPhone.

In late December, DigiTimes and Apple analyst Horace Dediu both mentioned Apple’s alleged investment in the ultra-thin IGZO displays produced by Sharp, predicting the inclusion of the technology in Apple’s next batch of iOS devices, including iPhones and iPads. Dediu also pointed to Apple’s recent $2.3 billion investment in “product tooling, manufacturing process equipment and infrastructure,” believing the cash was used to help bail out Sharp, which had been in financial straits in 2012. Sharp is reportedly going “all in” on IGZO technology, so it’s possible Apple saved Sharp to leverage its investment in the next generation of displays.

IGZO display technology is not only thin and tough, but it can even handle higher screen densities than Apple’s Retina display, which is visually stunning on its own. IGZO displays can reportedly handle display densities north of 330 ppi; for a quick comparison, the new iPad 4 can only achieve 264 ppi.

One of the advantages of IGZO display technology is its lower power consumption. Most Apple products, from the iPhone 5 to the iPad 4, require cartoonishly big batteries to achieve just eight hours of power -- this is because current-gen Retina displays are extremely power hungry. If Apple wanted its iPhone 6 to not only last longer during the day but also charge faster when plugged in, IGZO seems to be the way to go for the next generation of iOS devices.

Besides rumors about the display, however, there haven’t been too many other legitimate reports on the iPhone 6, but we have noticed a few interesting patents: A patent filed in March but published last September described tactile keyboards, flexible displays and laser microphones and speakers built into an iPhone, designed to conform to the user's needs. Flexible displays would allow for easier holding and typing, while the highly advanced tactile screens would create buttons when needed so users can feel "keyboard" letters as they type or touch the topography on Apple's Maps.

It's wishful thinking that Apple would include all these technologies in this year’s iPhone 5S or 6, rather implement them over time, but it's certainly fun to think about.

The full text from Steve Wozniak's speech at BusinessWeek's Best Brand Awards is available at German magazine WirtschaftsWoche.