Well.
Having looked over the IGC recently, I was struck by the nonstandard borders for the Aztecs, Iroquois, and Nippon (and at least one other that I'm not recalling offhand). It got me thinking. Shield shape varied significantly with location; for example (going by memory, since heraldica.org seems to be having trouble at the moment):
In Italy, the shield of a coat of arms was often a shape derived from a horse's facial armor.
In Iberian heraldry a squarish shield with a slight point at the bottom was most common.
In late French heraldry shields tended toward the same, but with pointed upper corners.
The only reference to oval escutcheons (as in EU2) in heraldry that I found was on
this page, which mentions that they were often used for the arms of priests and ladies, who were not expected to fight.
If nothing else, using squared shields would greatly simplify making quartered CoA's like Burgundy and Denmark.
The idea should have obvious applicability to Tolkien's heraldry, where shape is significant and the number of points reaching the shield's edge is of great importance.
Has anyone experimented with using strange shapes? I'd think the shield displayed in the upper left corner of the user interface, and also the small message indicators in the upper right for peace offerings and such, might be problematic.