I've pondered this & gone a bit radical. I've outlined an idea on meta:
http://meta.wikipedia.com/wiki.phtml?title=Wiki_markup_tables
The key details are: * one cell per line (and not one row per line) * formatting information is seperate from data
These both increase the clarity considerably. Someonoe who jsut wants to edit the data can skip the header line, no matter how ugly and comlicated it may be.
I've also put in details of table syntax from other wikis: the moinmoin style used at Meatball and the Wookee format that has been implemented on Unreal Wiki.
tarquin