The id_column is uneditable because by default, you shouldnt edit auto_increment columns, which for my purposes is about 95% of database tables I want to interact with. Any without this column can easily have this column added. It greatly simplifies the default saving/deleting cases to be able to assume that the ID is unique and not editable.
Obviously with more work, it could support editable IDs it just seems the complexity is probably not worth the cost. If a good design presents itself or patches are forthcoming, I would certainly consider / merge these changes. That said given that ease of working around this, I am a bit loathe to add complexity myself without a good design.
Cheers,
Russ
