Hi I don't know how feasible this is, but I was wondering if it would be possible for your developers to integrate some sort of service that would enable us to be able to use wifi based calling and texting (without using our minutes and texts) similar to how T-Mobile does that with their service. I don't know the technical details of how t-mobile does it, but if it could be done via the built in S.I.P client in android that would be amazing.
I know there are ways to do this using sipdroid + pbxes.org + Google Voice, or GrooveIP + Google Voice, but those solutions require third party apps and require people to dial a secondary number for incoming calls, rather than the simplicity that a native client would have.
The ideal situation would be this:
Uses the native SIP client that has been built into android since OS 2.3.3 (Gingerbread)
Requires no applications to be installed (with the exception of an APP that would be a setup/configure program)
Allows incoming calls to come in directly to the phone's number (rather than requiring a separate number like the google voice + GrooveIP solution does) and route them through WiFi if it is available, otherwise routing through regular cellular networks if a decent wifi connection is not available.
Allows outgoing WiFi calls to still come from the phone's number, and not some alternative number or alternative caller ID. (AKA, the number being reported to the receiver's phone is the phone's native number).
Routes outgoing and incoming calls, and text messages through wifi whenever such a connection is available...if said connection is not available it uses regular cellular minutes and texts.
All of this being done automatically.
I hope this feature is feasible, as I know quite a few of my family members who would switch from T-Mobile if ting had this feature. This would of course take a lot of development time, so to add interest to possibly develop this, I would like to state that this would be a feature I would easily pay $3-$5 for per month for, as I am sure many others would as well.
The ease and simplicity of having this be a carrier native feature would be a huge selling point for a lot of people, especially some who currently stay on T-Mobile for that feature alone (because it saves them countless dollars every month given the ubiquity of WiFi).
Anyways, thank you for thinking outside the box of most carriers, even most MVNOs. I Wish you many years of business success, for you are living up to Google's honored motto: "Don't be evil!" Let me know if this could be done, and also how difficult or easy it could be to achieve if you do decide to do it.