I find the dokuwiki table syntax to be pretty simple and effective, or the markdown extra version. Don't know why none has been made a standard part of markdown yet. Seems like it must be due to backlash against table-based web designs of the 1990s, (which resulted in an entire generation of web developers thinking that tables are inherently evil and an entire generation of non-developers who just do things in MS Word or Excel instead because it's relatively easy to make tables).
A standard can be descriptive (bottom-up) or top-down (prescriptive). A descriptive standard will only check and document common-ish features to implementations. Tables are not one of them.