My major concern is the ease of editing issue. I have
against good-looking tables and nice designs that make a page
easy to read, but if it makes the underlying code hard to edit,
it doesn't suit Wikipedia well.
Obviously many Wikipedians are willing to put in some effort to make a
nice page layout. Html tables make a page more attractive and
information easier to digest.
If Karl finds html table syntax too tedious (it is tedious sometimes), I
suggest he leaves them to others to add/maintain. But restricting their
use is like a person that orders a pizza everyday and objects to other
people still cooking their own meals.