Working with the Fuelphp orm I found it pretty annoying not being able to set instance variables for the model class. i.e. generating a variable like $post->how_long_ago giving something like "2 days ago" from the created_at timestamp field.
This extension allows you to generate "computed"properties (they are defined after the data has been fetched from the DB). My knowledge of the fuel core is pretty limited and I feel like this is a bit of hack but its been working fine for me and allowed much more flexibility in my models, check it out:
I'm trying to understand why you think this is needed.
The v1.4 supports custom properties on the object without problems, and to deal with data you should use an observer. So this functionality is available out of the box.