Agree about Emacs, and I used it already in MS-DOS back in the day. You could launch the compiler (or make, more likely) using M-x compile or use C-z to open command.com to run commands on the prompt and then exit from that back to Emacs. Almost like multitasking!

I never really liked any of the typical late-MS-DOS era TUI applications and have no nostalgia for those. I think a small TUI like a OS installer is fine, but I realised it is the command-line I like. Launching into a TUI is not much different from opening a GUI, and both break out of the flow of just typing commands on a prompt. I use DOSbox and FreeDOS all the time, but I almost never spend time in any of the TUI applications.

Despite that, I am currently working on a DOS application running in 40x25 CGA text mode. I guess technically it is a TUI, but at least it does not look much like a typical TUI.