Well it will come in models of course, but thats about right. It needs to be priced at, or below, what the 4S would have been priced at had it been continued. Next year - and this explains the 5 in the 5C - the update on this line is the 6C, built on the 6 internals. I am assuming the new phone this year is called the iPhone 6; however the 5c still sells at $100 or more less, similar to the way the iPod touch market works now.
There may also be a bigger screen model every year, maybe called the iPhone 6S. S for screen.
EDIT: So models this year - 2013/2014 - are the iPhone 6, and iPhone 5c. Next year, the iPhone 7, iPhone 6c, and the iPhone 5c.
Possibly also an iPhone 7s. Thats all they need, leaving the sub $300 market to Andoird.