We did talk about adding criticals, fumbles and combat manoeuvres to spirit combat in the S&P article but the article was already long and the system complex enough. Seemed like a better idea as a house rule or depending on the setting if you wanted to add flavour to combat.
For example, one way to do Binding would be to make it a Combat Manoeuvre. E.g. you attack, the foe fails their parry so you get a chance to bind it. You could also use CMs to allow you to flee, 'over extend' an opponent and so on.
If you expected to run a campaign with lots of spirit combat it would be a fun addition.