Not in the current stage of FxOS, since Gaia (the UI) seems to fail to deliver anything 'new' to a plain consumer.
For FxOS to really stand out in developing countries it would require a lot more than what it is providing now. In my opinion, since we are partly already doing communications for free trough Facebook and Twitter, something like P2P connections between the FxOS devices does sound doable for me, both for text and voice. In addition, if you could implement something like Twilio for actual calls it would strip down costs both for mainland and international calls. For reference, where I live calls trough Twilio are six to sixteen times cheaper than what my carrier can provide. This way, you would also avoid the need to sign a contract with a carrier. I believe that this form of carrierless phone would appeal to the crowd the FxOS is trying to reach.
For FxOS to really stand out in developing countries it would require a lot more than what it is providing now. In my opinion, since we are partly already doing communications for free trough Facebook and Twitter, something like P2P connections between the FxOS devices does sound doable for me, both for text and voice. In addition, if you could implement something like Twilio for actual calls it would strip down costs both for mainland and international calls. For reference, where I live calls trough Twilio are six to sixteen times cheaper than what my carrier can provide. This way, you would also avoid the need to sign a contract with a carrier. I believe that this form of carrierless phone would appeal to the crowd the FxOS is trying to reach.