Maybe, but history suggests a major update occurs every 2 years. Still, it wouldn't surprise me, particularly after the problems with the 4. A larger form factor though? That's just moving backwards imo
Everyone is screaming out for a larger screen size of 4"+. I know Apple normally does what it wants, rather than what the consumers want, but it appears they realise they will lose major ground, as all the other phone manufacturers are making some beautiful displays with 4"+ LED backlit screens. 3.5" really is too small now, and if Apple are clever reducing bezel sizes considerably, they will have a phone with a larger screen without sacrificing too much in the terms of size of the device.
Plenty of case manufacturers have gambled on this, and leaked CAD drawings, designing cases ready for launch.
There is no point Apple releasing just an iPhone 4S. I gamble on the 4S being the new budget phone, with A5 CPU and 8GB storage only.
Think about it, why would their naming conventions go like this:
iPhone - 1st Generation 2007
iPhone 3G - 2nd Generation 2008
iPhone 3Gs - 3rd Generation 2009
iPhone 4 - 4th Generation 2010
iPhone 4S - 5th Generation 2011
iPhone 5 - 6th Generation 2013 (possibly with current hardware schedule)
iPhone 5S - 7th Generation Late 2014
Its more likely in my opinion, that the naming conventions will be kept like this for the near future:
iPhone - 1st Generation 2007
iPhone 3G - 2nd Generation 2008
iPhone 3Gs - 3rd Generation 2009
iPhone 4 - 4th Generation 2010
iPhone 5 - 5th Generation 2011 (iPhone 4S new updated iPhone 4 budget model)
iPhone 6 - 6th Generation 2013 (iPhone 5S new updated iPhone 5 budget model)
iPhone 7 - 7th Generation Late 2014 (iPhone 6S new updated iPhone 6 budget model)
Of course, its all speculation. All will be revealed in just over 1 week.