There is nothing more frustrating than creating a long trigger with lots of actions, then you realise you have missed one out. There is no way to create the additional one and re-sort the list. You have to delete every action up to the point where you need to insert the new one, then recreate the rest of the actions. This is hugely frustrating. Especially when you are 'trialling and erroring' a trigger.
Hi Chris, this feature to re-order actions on the trigger is now available. Please contact the Support Team if you have any further questions.