There are plenty of things I would like to see return.
But the main titles I was disappointed to see disappear from the DCYou were Midnighter and Martian Manhunter. But as far as I gather despite being awesome books they didn't sell too well, so I guess there wouldn't be much point in just re-releasing them. I guess hopefully Midnighter might start showing up in Nightwing as they had a pretty good dynamic going on, but as for MM, I don't really see him joining any lineup in the foreseeable future which is a real shame - and I'm not a lifelong MM fan, only really got into him with the last run.