In the old games there was a item tracker which let you find hidden items. It was pretty cool. So maybe implement that. Perhaps spawn items? (poke ball shapes all the time) then make a separate item tracker device like the poke tracker. Another note, I wanted to say is with the evolution stones. I know they're rare but I've filled my inventory twice going to hundreds of poke stops and have not seen a single stone. With respect to old games, they were more available especially when you reached end-game.
We don't have hidden items. We only have Pokestops. Yes we know stones are rare. I have done the same, they might be tweaking it in the future.
I wanted to take the time to ^Bump^ this thread because I too felt a great deal of satisfaction finding someone's randomly thrown Greatball in Amber City. -TWKY