Apple's rumoured release date for its next smartphone iteration will gain more traction if the focus is on the iPhone 6, which is a full-upgrade effort instead of the incremental bump ups that the iPhone 5S reflects.

There is no way a 4-inch handset that is the iPhone 5S will upstage Samsung's Galaxy S4, with its 5-inch Full HD Super AMOLED display screen, quad-core processing muscle and Smart software features, Ken Segall said.

Mr Segall worked as Apple's marketing consultant.

But beyond the hardware and software specs, he is convinced too that pursuing the 'S' business model is detrimental to Apple's interest while dousing consumers' interest for the next iPhone refresh.

"More important, tacking an S onto the existing model number sends a rather weak message. It says that this is our off-year product, with only modest improvements," Mr Segall further argues.

Consumers, he added, would want to "get the latest and the greatest," in snapping up a new gadget, adding that delivering the best upgrade choice should be the focus of Apple.

Analysts believe Apple is working on killer features that will allow the new iPhone models to easily defeat the top-notch Android handsets to come out this year - led mainly by the Galaxy S4, HTC One, Sony's Xperia Z and the rumoured Nexus 5 from Google.

However, many also expressed doubts that most of the power-packed specs will miss out the iPhone 5S due time and production constraints.

Instead, killer features like fingerprint sensor, digital wallet via NFC technology, camera upgrades and LTE radio signals with wider coverage will have to wait for the iPhone 6, which blog reports said will be pushed by Apple on Q1 2014.

One more thing that will make the iPhone 6 a better release option is its screen size, which analysts said will likely stretch to maximum 4.8-inch, making it competitive to any of the smartphone size it will tussle with.

The so-called Apple phablet will battle it out with the upcoming Samsung Galaxy Note 3, which is pegged to get a 5.9-inch display screen plus an 8-core Exynos Octa 5 CPU.