Is there a summary anywhere of all the leader/races? It would be nice to see a list that showed all the unique features that they start with. Summarizing the following: starting mana, Palace effects, hero, world spell, effect strengths/weaknesses, traits, unique buildings, unique units, and other pertinant facts. This would help when starting a game, but also when meeting your opponents.

Much of it's in the Wiki (not sure if that's working at present though, it goes down periodically). It's also probably not up-to-date for 2.030.
The strategy subforum of this one also contains some pertinent info for some races.

The team are, understandably, holding off on documentation until Ice or possibly after - it creates duplicate work when things keep changing so frequently. Unfortunately that can be rather overwhelming for new players.

I will update the link in my sig before too long. At the moment, nothing will be up-to-date. :)

That is perfect! Please let me know when you've updated it. I started to create a spreadsheet (at work when I couldn't focus on what I was being paid to do...), but couldn't remember a whole lot of it.