Problem: When editing a table in wikitext, it is possible to add CSS properties to rows and to cells, but not to columns. When a property applies to an entire column, we are compelled to copy-paste this property in every cell of the column; it would be easier and shorter to write it only once, at the beginning of the column.
Proposed solution: Enable in some way the use of the <colgroup> and <col> HTML attributes within {| |}.
Who would benefit: Contributors who create or edit tables on any Wiki project.