Are you doing any complex objects in the form that can be changed to string presentations and execution lookups?
If you have fields that take open text entry (like a search box), set a length limit in the action to return null until a text length is reached.
single field ognl conditional expressions. Run one thing if... or run the other thing. In cases where you might have execution duplication in competing actions on hidden fields, etc.
That is all I can think of at night from home. Maybe tomorrow I will have a few more semi-educated guesses.