I would really like to see an ID field. It does happen that I want to e.g. close a task because it is a duplicate of another one and therefore would like to just shortly right the ID of the task instead of e.g. having a link to the task in there.
Also useful for reference when talking to somebody.
The ID should be long enough to be unique within my company, though. As I am talking to different people in different projects all the time.
If you want to avoid making it to technical…
The ID could not be in the view by standard, but could be added to the view if I wanted to: Customize View - Enhance Functionality