So Riddler's plan was to just make Batman bored of finding his stupid trophies?

worked for me. I didn't 100% any of these after Arkham Asylum.

I LIEK CHOCOLATE MILK

in knight he taunts bats a few times about how he's waging a war of attrition on his neurons, whittling them down with each trophy collected

so basically bamham riddler just plain doesn't understand how being smart works lol