Please add some detail, especially about why you think choosing an AVR wouldn't be future proof... Without knowing your aims, we cannot help...
(Also, I have to mention, there are 32bit AVRs too...)
There are quite some factors one needs to assess when going into production. EVen though a given microcontroller might not seem "future proof" because for example performance regarding possible future designs, its cost advantage might make it the preferred choice. $1 at 10000 pieces makes for $10000!
Also, I'd consider power consumption an important factor too, a simpler device usually consumes less.
The third aspect I'd take into consideration is the availability/usability of the development environments available. I'd even consider doing the prototyping on one uC, with a more convenient development environment/support, then when the product is functionally operating, before the mass production, I'd choose a cheaper, more tailored approach - even if the environment is lesser to the other one. This way the prototyping is done quickly, and the first few usability issues would be cured quickly, and in the less convenient environment, onlz a small amount of work must be done.
I usually prototype small projects with Arduino, then for example I switch to ATTiny2312, or smaller uCs, when applicable.