If the 8255 shouldn't be used, I don't see any reason why a CPLD version of it should be - programming logic devices isn't a goal in itself here, I presume.

As I indicated, this device - any many other ancient products - HAS its use in learning how to control I/O devices.

Don't get me wrong in that I thus would suggest that if you want to learn how to make computer programs you'll have to sit behind a PDP-11 with a teletype terminal, or if you want to make a control system it's best to get the specs of a SC/MP to start with. But I've always been told that it's a good thing to start with the basics - and that's what the 8255 provides in a sense.