Discussion 1
I agree that Bash is a good preference for the Linux shell because it has all of the features that an average Linux user would need. Granted that Bash does not have the advanced features that other shells have and that other users may need, I think that for students like us who are beginners with Linux, then the Bash would be a good shell to learn. Moreover, since it is the default shell used on Linux systems, then it will most likely be available from any Linux system that students access. This would save them a lot of trouble from having to install a shell on every new Linux system they access. I also agree that using Bash would provide a user with a wide network of users who can serve as sources of support or information. Not only are there many users who are well versed with Bash; even the sh users can become resources, since Bash was largely derived from the sh shell.
Discussion 2
I agree with the reasons you provided. By being derived from sh, it becomes backward compatible with sh; hence, making Bash scripts run on older Linux systems. However, because Bash also has capabilities of the C shell and the Korn shell, Bash provides Linux users with more features than the sh shell. Another reason for Bash being the de facto shell on Linux systems is that it uses the default Linux library bin/sh. Other libraries may have to be defined when using other shells.
As well, I think that Bash is the de facto shell for Linux systems because it is very similar to DOS, which was the predecessor of Windows and which Windows users still use. As such, having the Bash shell as the standard shell in Linux will make it easier for a Windows or DOS user to transition to a Linux system.
Bibliography
AskUbuntu. (2015, June 20). Why is bash the default shell in most OS? Retrieved from
http://askubuntu.com/questions/638918/why-is-bash-the-default-shell-in-most-os
Quora. (n.d.). What is difference between bash, zsh, tcsh, sh etc.? Which one should I use?
Retrieved from https://www.quora.com/What-is-difference-between-bash-zsh-tcsh-sh-
etc-Which-one-should-I-use.
Quora. (n.d.). Why is bash the default shell in Gnu/Linux distributions? Retrieved from
https://www.quora.com/Why-is-bash-the-default-shell-in-Gnu-Linux-distributions