Adding to some of the points above on item-based objectives... It's nice if the items you're securing provide relevant in-game effects, and I don't means getting Item A allows you to get Item B to open Item C.
Simply capturing and holding missiles or nukes or whatever else is nothing more than CTF without Flag. I personally never care about points tallied after the game.
If you recover a lost satellite phone/radio that allows you to call in regular resupply or intel or other Game Master Plot Event, that makes an item objective worth searching/fighting for.
"The Bird of Hermes is My Name, Eating My Wings to Make Me Tame."