With the latest updates and 10.5.3, I have disabled WYSIWYG font display, deleted all the files specified, and rebooted.
Word now starts in 15 sec best case. Best case is right after starting and exiting. In more normal cases it's like 30 sec. It rebuilds fonts even when no fonts have changed, not all the time, but times when it shouldn't.
15-30 sec would be fine for Photoshop, but it's scandalous for a word processor. However it's much better than several minutes, which is what I had before.
Currently I use Textedit to display Word documents where possible, using Word only when I absolutely have to have compatibility with a PC user.
This needs to get fixed.