PCI bus is required

I see no reason why software would even be aware of which bus type the the hardware is using. In Macs for instance, ported software often throws data meant for an ISA bus into the Nubus of the Mac with no noticeable issues. There is the bus speed issue. In this case, it would make much more sense to list minimum bus speed as there are varied speeds of PCI buses that are both faster and slower than other bus types.

However, if a company wants to say "PCI bus" in their system requirements without stating bus speed, "PCI video", "PCI sound card" or something similarly sane, then tag it and note the insanity in the tag note.