We've found Collector to be especially useful for features that have already been created but need attribute updates by the field crews -- since they are the ones physically touching, installing, repairing, etc. The features symbolized the work completed -- a hydrant was flushed yes or no -- a storm main was cleaned yes or no -- and the symbol showed whether the work took place on a particular feature -- a red hydrant (no) turns green when flushed and the field changed to (yes). The field crews loved it, because they could see what they accomplished!
However, beware! What I have learned, if you change a symbolized field, all attribute fields will change to the feature defaults.
I propose that this not occur! Collector is a great tool for editing individual features. Most field crews only want to see and have access to that feature class they will be working on in the field. If this feature is part of a geometric network you do not want them creating this feature in the field. In most cases, I turn off the ability to create when creating the service.
With that in mind, maybe the application can know -- if a new feature is being created then populate default values; else don't change the existing values.