I don't think that objects are heavy-weight at the moment. The acs_objects table has less than 10 fields - adding a few fields doesn't hurt especially if they are accessed frequently.
And space - harddisks are cheap and huge these. We can drop a few useless indexes if space becomes a pressing issue.
I'd add as many fields to acs_objects as necessary. I count 307 occurences of "acs_object.name" in HEAD - imho adding the name field makes a lot of sense.
