A large part of the opening run of Season 4 episodes has focused on setting up Legends of Tomorrow (just incase it wasn't already obvious), with one of the major ways of doing that being to bring back Ray Palmer, another not-dead character. I can't complain too much about that though, because even just in the two episodes he's been back it's clear how great Ray (and Brandon Routh) is on this show. He brings an air of lightness and goofy humour that the other characters just can't, no matter how much they want to lighten the show. However, while we got to see him ATOM-suit up in this episode, it may be the last we see of him on the show, because although he'll be on Legends (which looks really fun, despite the annoying setup), his purpose on this show (aside from quips) has probably run its course.