With the iPad name they will probably only sell two at the same time..the current generation and the previous generation. So they can get away with the old generation being just "iPad" and going with "The new iPad" for the new generation. With the phones they're selling multiple iterations at a time so it's a little trickier.
My thing about this new phone being called iPhone 6 because of the 6th generation on iOS 6 with the A6 processor (if it ends up an A6 and not an A5X) is what do they do in the future? 3G to 3GS. 4 to 4S. If this 2012 phone is named the 6 and they go to 6S next year (same form factor..faster internals) what happens in 2014? Presumably, that'd be the 8th generation phone on iOS 8 with an A8 processor. Would they call it the iPhone 8?
iPhone - iOS 1 - 1st Generation - ?? Chip - 2007
iPhone 3G - iOS 2 - 2nd Generation - ?? Chip - 2008
iPhone 3GS - iOS 3 - 3rd Generation - ?? Chip - 2009
iPhone 4 - iOS 4 - 4th Generation - A4 Chip - 2010
iPhone 4S - iOS 5 - 5th Generation - A5 Chip - 2011
iPhone 6 - iOS 6 - 6th Generation - A6 Chip - 2012
iPhone 6S - iOS 7 - 7th Generation - A7 Chip - 2013
iPhone 8 - iOS 8 - 8th Generation - A8 Chip - 2014
iPhone 8S - iOS 9 - 9th Generation - A9 Chip - 2015
iPhone 10 - iOS 10 - 10th Generation - A10 Chip - 2016
iPhone 10S - iOS 11 - 11th Generation - A11 Chip - 2017
They'll probably be off identifiers by then but this is fun.