I dunno what CP/M you were using, but all the rest of us had application specific patches for Wordstar for whatever we were running, and pretty much everything else. The Wordstar branded for Osborne did not work right on a Cromenco+VT100 and definitely went weird on a TRS-80 4P without directly patching it. Don't even get me started on the cornucopia of floppy disk formats one had to deal with.
Not sure what the VT100 link was supposed to prove other than yeah terminals back then were hard to support generically. And you had to hack around the issues. Which was my point.
The "Osborne-specific version" was the retail version...for the Osborne. Yeah, there was a 'generic' retail Wordstar...that you had to patch for your specific hardware if your combo wasn't supported out of the box. I had friends who's whole business back then was hacking popular CP/M apps to support less popular hardware.
There wasn't some compatibility nirvana. It was just easy to hack up a fix because apps were on the order of 10's or 100's of kilobytes, not hundreds of megabytes.
Nostalgia is a helluva drug.