I too have experienced the exciting "Your Seeker Droid Found Something" message (can't recall it being interesting) on Makeb in the Hutt Strongholds area, only to dig up a worthless grey item. It didn't deplete the area though.
If this is indeed working as intended, then the devs ought to hang their heads in shame. What a waste of everyone's time !!
I'm not one for mindless seeker droid digging and so this has really put me off the whole thing.
Shall we predict that a Cartel Cash Gouge Item will appear soon to increase the chance of getting better loot ?