Personaly, I'd prefer the tech tree and map(s) to be available as printouts from the game disc.

I'd also prefer there to be "layers" of options available in those printouts as to how much detail and info you (the player) want to have available.

Maybe I want a tech tree in my hand that gives me what troops come from what buildings for my faction alone. Maybe I want that same info for all the factions. Maybe I want the tech tree that gives stats and notes on usage for unit types... maybe one that also has a little bit of historical info on what the buildings represent, or which of the cities/castles represented in my faction were most likely to have had such buildings, etc etc.

On maps, maybe I want the one global printout. Maybe I'd like the printouts of each geographically discreet area with greater degree of detail and some strategic info on where choke points might be found and tradtional avenues of approach for enemy forces.
Or maybe I want the print out of a specific region with full tac inf and terrain layout with what sort of terrain will be most likly triggered by a battle in specific areas so I have some better clue where to pick my fights.

This wouldnt be that hard to do or take that much in resources to develop. It couldnt be done in old school foldout type production mats but it could be made avaialbe for the player to print out as desired from the dvd or even sold as a seperate "support" dvd if it would cause the need to add an additional disc to the production.

For sure and for certain, I'd much rather have the above type info in the game I buy, rather than a "making of" disc which I'll never load, never watch and have no desire to possess.