My opinion after owning a samsung sg2 - it's nice to have a larger phone screen - but it's actually not that nice to have a device that is all in one- at least not at the state of the art we are at currently. What I'm talking about is devices doing it all. There is no such thing as no-compromise one solution.
You want a large phone screen, you're gonna compromise on a few things: size of the device to fit in your pants, pocket, etc. Convenience of using that bigger device. Battery life to power the larger display. Quality of the display (though now in late 2012, you have 1280x768 4"+ screens).
Sure some phones offer great displays and large displays together, but more often than not the size and weight will not be a real bargain for many. I still believe having separate devices would be the best no-compromise solution. Even if they allowed the ipad mini to be a phone/make phone calls, you wouldn't put it against your head. Using a bluetooth headset is nice but that's also not convenient for many. And who wears their bluetooth headset all day everywhere they go? Unless you are a some employee who needs to make constant phone calls, you'd resemble a complete douchebag wearing that thing all day long.
Since I've bought the ipad mini, I've not used my iphone 5 for web surfing. It's solely used for texting, some flipboard when I can't use my mini in a very crowded area, starbucks passbook option, and my primary camera. Other than that, it does what it does, make facetime calls on the go and used as a phone to make calls.
Look at the samsung note1/2 - that thing is so big, it looks absolutely stupid to hold it against your head. Sure some people will still buy it and use it as a phone, but it's too much of a compromise in my own opinion. You can just use your phone while using a tablet and have best of both worlds.