Do you really want to have to fix your equalizer if you accidentally select a bookmark when you just wanted to listen to music? And if you've been listening to audiobooks then go to select an album, you'll still have the audiobook's bookmarked equalizer on.
Why not just save config file presets and use them to quickly switch?
Bookmarks save the shuffle mode because that affects the playlist order, so you can't properly bookmark a playlist, including what to play next, without bookmarking the shuffle mode. Equalizer has no effect on where in a playlist you are, and doesn't really belong in the bookmark.