Here’s an idea we toyed with.  Aside from the squares not firing, there was the occasional complaint about a line not being able to fire just because a small part of one base was blocked, especially a large 4 base battalion that still had three unblocked bases.  Some also dispute the lack of fire from a column.

One could allow ANY base(s) in a battalion to fire, but with a (-1) penalty per blocked base.  Thus a square with only one face able to fire would do so at a (-2) penalty, as would a column.  If cavalry attacked the square’s corner so 2 faces could fire, then the penalty would be (-1).  We allowed large battalions in line to ignore the first blocked based and begin the penalties with the second blocked base..