Developing World Phone

"The hacker doth protest too much, methinks."

The big issue I see here is the battery. You've got a set of tradeoffs that I suspect are going to result in different choices for feature phones in the developed vs. developing world:

The bigger the battery, the greater the cost.

The bigger the battery, the longer it can go without recharging.

The bigger the battery, the longer it will live (all things being equal (and it's more complicated than this, I gather), the lifetime of the battery is strongly coordinated with the number of recharge cycles).

Lithium-ion batteries have a finite "shelf-life", time and heat (including ambient) are enemies.

So given the above, you ideally want the smallest battery that provides adequate time between charges and that dies from exceeding its maximum number of recharge cycles about the time it would die from plain old age and/or when the phone itself will die.

Making the battery bigger than this is wasted cost (including size and weight), unless you need the larger capacity for some reason. "Developing world" phones may have a bias towards larger batteries since large parts of it have higher ambient temperatures. Various parts of this market are willing to trade off the higher cost of a larger battery because the opportunity to recharge whenever you want to is not there (many countries don't supply electricity 24x7, many areas don't supply it at all, you need someone's generator).

And of course in the "developing world" cost is a even more important consideration.

BTW, for my own reasons I too have a Nokia "developing world" candy bar feature phone, a 1600 I bought near the end of 2007 (http://en.wikipedia.org/wiki/Nokia_1600). It's now discontinued, and I suspect from comparing it to your 1616 that the latter is its replacement. Yours has a slightly smaller battery (800 vs. 900mAh) with a longer standby time and a much longer talk time:

http://www.gsmarena.com/nokia_1600-1188.php

http://www.gsmarena.com/nokia_1616-3007.php

My current phone is a Nokia 1208 - it offers all necessary functionality, a good battery life and was cheap to buy unlocked. My only criticism is the phone's thickness of 1.7cm - and that's why I'm interested in the C-models.