Did Wizards ever write a followup for the 2003 card face redesign?
The references section of the Card Frame article on the MTGSalvation Wiki refers to a large number of articles published by Wizards about card frame changes. The ones about the Eighth Edition change that you're asking about are:


Card Frame Redesign FAQ, by the magicthegathering.com staff.
Frames of Reference, by Mark Rosewater
A Scary Card Frame Story, by Randy Buehler


The article most relevant to your question is Frames of Reference, because it is where Mark Rosewater explains why exactly they made those changes.