I think the best option you have is to recreate your super playlists as a single more complex playlist.
When you are editing a smart playlist you can option click the '+' button (turns into '...' while you are holding option) and this creates a subgroup that can a condition of it's own.
This playlist picks music based on rating and last played choosing higher rated tracks more often:
One technique I used in some playlists was to put NSFW tracks in a playlist and then build other playlists to exclude NSFW tracks. Putting tracks in a playlist is an easy way to add additional information about them without having to edit the ID3 tags. That doesn't work with these more complex smart playlists.
You will have to put additional information like that into the ID3 fields. You can use the comments block for this, but I don't like to do that because I like to be able to add this kind of flag to multiple tracks at once and I can't do that as I may be losing comments already entered. Genre works if you're willing to use that instead. Any field will work; as I don't have tracks that use grouping I used that for my own NSFW tags.
One slightly more complex place to put these kinds of tags is the 'Category' field. iTunes keeps a category field but doesn't show that field in the editing UI so it's normally not used for anything. Doug's Applescripts offers a script that will let you edit this field. (script and instructions)