It is a regular thing for Linux/Unix people to talk about making a "better terminal". The irony of your talking about Windows in terms of "the terminal", is that pretty much all of the ideas that people put forward for making a "better terminal" have actually been done, decades since, in the worlds of MS/PC/DR-DOS, OS/2, and Windows NT. OS/2 version 1.0 had the MOU, KBD, and VIO subsystems, which introduced device independent input event streams, 2D screen buffer addressing, a handle-based API, and API calls rather than escape and control sequences. Windows NT took this further into the Win32 concept of a console.
* http://jdebp.eu./FGA/tui-console-and-terminal-paradigms.html
Command-line interpreters are not terminals, either. Powershell doesn't modernize "the terminal".
* http://jdebp.eu./FGA/a-command-interpreter-is-not-a-console....
And the most common interface between programs has never actually been the C ABI, not on DOS, not on OS/2, nor on Win32/Win64. The most commonly used convention has to be the one used by applications softwares to make system calls. Thus the most common calling convention on 16-bit OS/2 and Win16 was in fact the (Microsoft) Pascal calling convention. 32-bit OS/2 and Win32 used different calling conventions, APIENTRY and WINAPI, that still weren't the ones used by plain C functions unadorned with calling convention specifiers.