Well, yes, the Panther default is now bash. Big deal. If you don't like it, start up 'netinfo' in your utilities folder and change the shell in your user entry. They haven't removed tcsh from the system, it's just not the default anymore.
Shells are a religous issue; it just depends on what you are used to. If you have a BSD background, you're probably more used to tcsh/csh. If your a System V weenie, you're likely to be a korn shell (ksh) type. If you're a masochist, you probably still use the bourne shell (sh, although it's usually aliased to ksh or bash these days). Bash is the GNU shell that is sh/ksh-like, plus a bit of csh, plus some additions. Generally, bash will run sh/ksh scripts with little or no modifications and provides the command line editing, history and alias features provided in ksh. Try it, you'll like it.