The producers have pretty explicitly said that he won't be shrinking down. Even though Arrow and The Flash take place in a shared universe where super powers like that now exist, that would definitely be something more suited to the latter, where blatant super humans are the order of the day. With Arrow, the closest to that territory they've gotten is the Mirakuru.
So if he isn't going to shrink down, I'm interested in seeing what they do. It should be noted that they were originally going to use Ted Kord/Blue Beetle for this role but then changed it to Ray Palmer at the last minute. Since Blue Beetle is a tech based hero, I wonder if they go that direction and just have it as a powered exo suit? I also find it interesting that the Queen Consolidated blueprints Palmer was looking at earlier in the season had "OMAC" on them.