There's been a lot of talk about whether light armour should be better than heavy armour, but as far as I can tell it isn't actually any better.
At level 1, heavy armour has 5 points of AC on light, which is cancelled out if you build a DEX/INT spec'd character. When you level up, the extra bonuses you get from magic heavy armour cancels the points you get from extra stats. So if you spend on DEX or INT as heavily as it's possible to do (ignoring things like epic destinies), then you're at the same level as someone tooling around in heavy armour.
Yes, class features can bring that up for light armoured characters, but as far as I'm aware, most of those either come on characters with restrictions (ie you can't use a shield), or on characters that don't get armour at all as standard... And most heavy characters get shield proficiencies too, which gives them easy access to more AC.