Two proposals for the 'Heroic Epic' and 'National Epic' national wonders.
1) Neither of these wonders describe buildings or monuments -- they are texts that define the culture of a given civilization. In that case, wouldn't it make more sense to classify them as 'projects' rather than 'wonders', since they are non-physical? More importantly, since these documents shape culture across an entire civilization, shouldn't their effects be more 'wide' than 'tall' -- affecting every city that belongs to a civ, rather than providing an outsized bonus to only a single city? For instance, Heroic Epic might give +10% production for military units to all cities, rather than +100% production to a single city.
2) I am not a programmer, so I have no idea whether this would be possible, but once a civ constructs their 'National Epic' or 'Heroic Epic', would it be possible to generate a separate screen (similar to the box that displays wonder movies or the founding of a new religion) with a background image and text from that civ's specific epic?
That is, say India constructs a National Epic. When the wonder (or project) is finished, a screen pops up with an image of a Hindu frieze, with text excerpted from the Ramayana. The Heroic Epic for Rome would be a passage from Virgil's Aeneid (a different passage might be used for Carthage). France's epic would be the Chanson du Roland, the 'Song of Roland' that celebrated the age of Charlemagne.
This wouldn't necessarily need to affect the building description itself (France could still construct the wonder called 'Heroic Epic') but there could be a few lines of code so that, when the wonder is finished, the game determines which civ built it and pulls up the relevant wonder screen. Alternately, each civilization could have their own individual epics listed as 'Unique Epics' or 'Unique Projects', so that France could actually be constructing the Chanson du Roland displayed on the city production section.