If we're going for realism, a guy in a suit with a Hoodie and mask is more believable than the aforementioned other two.
OK, I'll meet you half way and see if we can invent a good Riddler look.
I'm willing to work with the hoodie just for you. How about a Mr. Robot kind of genius but autistic type character; Elliot with the hoodie but he favors army surplus cargo pants and dark greens. Maybe he's more of a survivalist type too in the sense of being brilliant but also a loner. Manifesto kind of guy like he is now. It's really not too far of a stretch from where he is now.