Is a Swiss Army knife (SGML) over-engineered compared to a knife and fork (XML)? For the people who need to do complex things, no. For the people who need to do a few simple things, yes.
I like the sentiment of the post but I have always seen the Swiss Army Knife as the epitome of under-engineering. Capable of doing everything .....badly.
No dis on SGML over which I plead ignorance, more wondering whether that's the apt analogy for it.