Wally West is back. The original Wally West is back in DC Rebirth. (Yes. I am happy.) He is getting a new costume and it looks good.
The new Wally West will join a new version of the Teen Titans. That could be good. Maybe he can develop in that role.
Rebirth is a way for DC to reach to readers who have stopped reading the books in the last few years. It is also a way to re-establish legacy/history, which has been lost. I hope it works out.
There is a new Quasar. I am okay with it. I think it would be nice to have the original Quasar in action. The new Quasar is a woman and she will appear in Captain America, I believe.
Speaking of Captain America, he is apparently an agent of Hydra now. This seems to make no sense but the story just started, so it is best to withhold judgement. Sometimes stories that seem to have a unlikely premise work out.