well, there's nothing wrong with alter column restart, unless it requires special permissions on the executing user (to alter table). Would be nice if there was a way to do that without that sort of permissions.
about point 2, I didn't deduce that is the case, I just assumed. I was running a stored proc that does:
delete from table
alter column restart id
many inserts ...
and the job was failing and on the extremely long log I could see attempts to drop all constraints, then beggining a rollback and then attempting to recreate all constraints. Then I removed the alter statements and the job worked fine. I assumed the alter table would cause the drop/recreate constraints and that my user wouldn't have the persmissions (which would trigger the rollback). Again, this was just a long shot trying to explain something I didn't understand and I couldn't find anything to support this theory on the net so I thought I'd ask here. Any help would be greatly appreciated.