I was pointed to this topic bij doze, because I was thinking about a standard of defining what a snippet can do. One of the implementations would be the TineMCE plugin YOU just posted (funny how when you think of something someone beats you to it

) So I really love your snippet/plugin.
To complement your suggestion of the xml style tags for snippets.. maybe it’s an idea to pre-parse the content fed into the editor by replacing the [[ ]] style with the XML style to fit it in.. and before committing to the DB parse the content output of the editor back to [[ ]] style again.. that should solve your problem.
about that universe

IF... modx tags would become xml compatible I suggest they look like this:
<modx:snippet name="MySnippet" value1="This" value2="That" caching="True" />
The tags would be recoqnizable as being modx by using it as a namespace and complementing it with the tag type. You can then use:
<modx:chunk name="MyChunk" />
for chunks etc..
if a snippet gets values from another snippet you would get:
<modx:snippet name="MySnippet" value1="This" caching="True">
<modx:value name="value2">
<modx:snippet name="MyOtherSnippet" value="This" caching="True" />
</modx:value >
</modx:snippet>
ofcourse you have some more typing to do when using xml instead of modx tags but that will be solved by your handy plugin