Different page types (for example articles in main namespace and templates) have different concentration of different markup elements and it is not trivial task to color all wikitext markup elements since the combination of colors is much less than the combination of wikitext markup elements. Also tastes of editors likely different.

The availability of using different color themes in CodeMirror should help in this case.

Kinds of color themes:

• Light color theme for articles in main namespace (used by default)
• Theme(s) for people who are color-blind
• Several themes covering different editors preferences (need feedback)
• No syntax highlighting at all (T419339)

Theme selector may be placed on CodeMirror toolbar (T95148)
Also it is possible to add several useful buttons for enable/disable highlighting active line (T162204),
highlighting text inside extension tags and etc...