Word erase

First, thank you for reporting this.
In line 326 of ed.defns.c in the tcsh source package is:
F_KILLREGION, /* ^W */
Ctrl + W is set to kill-region for the emacs mode, which is the default mode. In VI mode, it is set to F_DELWORDPREV. I think this is the source of the confusion.
kill-region "cuts" everything from the beginning of the line to the cursor, while Ctrl + U just does the whole line. Such is the default behavior.
You can set your version shell variable to include "vi" to get back the behavior I *think* you're used to.
I'll mark this as rejected, please reopen if you feel this to be incorrect.

Ahhh, that did the trick. I should have done my homework more carefully. :$

Normally a shell listens to the EDITOR variable but tcsh needs "bindkey -v". I also think that it is a weird decision to make emacs the default instead of the classic vi, especially since the emacs mode totally ignores the stty settings. (this has nothing to do with emacs vs. vi!)

Anyway, thanks you for your help. You are really helpfull and fast. :)