not with the specs; also remember it would not get (iOS) supported pretty soon. may be at the maximum 12 to 18 months.
But if they put better specs in a lower-end phone... it's no longer a lower-end phone.
If the iPhone 4 had the 4S processor in it... it would be the 4S.
I know, I know... there were other improvements... but you get my point.
So let's say Apple adds a $350 model to go along with the current $450, $550 and $650 lineup.
Would they need four different processors? Four different camera assemblies? Otherwise it will be difficult to differentiate the models by specs.
If Apple's plan of "selling the older models cheaper" goes away... will they have to come up with four new phones every year?