My take on how the setting should be:

1) Magic should be common. Very common. MAYBE not to the "magic is cheap" level of 3.5, but people who haven't lived in a tupperware should have heard of it and seen it, and arcanists and clerics are respected and accepted members of society.

2) Magic should be as powerful as presented in the new PHB, no more, and no less.

3) As close as it is necessary. Which is to say, the setting should have it's own politics, divorced from those of the real world. Whatever similarities happen should be coincidences.

4) The themes should be Safe (There is law enforcement made of reasonably high leveled characters, and the rulers who didn't inherit the throne should be off the charts in power, as fits someone who made it to the top), Cold War (But not among ALL the nations, just a few), Change (We could use it to introduce the Dragonborn as major players, or to explain the rise to prominence of the tieflings), and my own little theme, Practical. A world with Practical would be one where the rulers actually looked at what magic can do and said "Hey, why are we wasting so much land on farming? We could mass produce items of food creation and eliminate famine forever!", for example. It's ridiculous that the governments never try to get some use out of magic, when anyone reasonably intelligent will have noticed what can be done with it.