Creole is supposed to be used all over the Internet to write in many languages using many scripts, by many users using various software and hardware. It's important to not create additional obstacles for people who use different setups than we.
We should AvoidTextTags, as they only have meaning in one language. Translating the tags is not always possible, and creates more problems -- especially in multilingual wikis.
Another important fact is that there are many different Keyboards with different layouts, and not all characters are easily accessible for all users. Therefore, we must AvoidSpecialCharacters in order to make markup FastToType also for people with different keyboard layouts than ours.
WikiWords used to form links are pretty useless in scripts that don't have the notion of lower- and uppercase letters.
Reading direction also varies for different scripts, so care must be taken to not use any "directional" constructs to mean "forward" or "back", as the meaning can change with the reading direction.