Well, we certainly are about to have a lot to talk about, thanks to "Rebirth".
Wally West
DC (I'll say it: that really means Johns because his fingerprints and name are all over this) is being especially clever this time around. While a generation of fans were squealing, "WHY FOR YOU BURY WALLY WEST IN THE COLD COLD GROUND?!", DC was busy behind the scenes making red-haired Wallace the central character and narrator of Rebirth #1. Nice one, DC.
And that certainly makes ME happy. Not because I care about red-haired Wally. I don't. Frankly, I always thought he was kind of an insecure, dim, screw-up with codependency issues. With Barry first and then with his mom and then with Linda "The Beacon" Park. Especially do I not miss Linda, who was never anything more than an arbitrary Ultimate Love interest for Wally as some sort of latter day compensation for the man-whore days of his early run, and who never had a personality of her own beyond that. She had more personality/job/look/outfit changes than a Captain Action doll. It's really hard to get a bead on a character like that.
Sure Iris West was terrible, but at least she was CONSISTENTLY terrible, you know what I mean?
Anyway, seeing red-haired Wally return makes me happy simply because it gives me hope that all the thirty-somethings can please shut up now and stop whining. Particularly since the Wally they are missing is actually the wise-cracking one on Justice League Unlimited and has very little to do with the hapless fool in the comics with that same name.
It won't stop their whining, of course. Because Rebirth Wally is not The Flash, but the Kid Flash...which is what he was created to be. I'm glad that DC finally, instead of forcing us to want what they are giving, has decided to give us what we want. But within reason. I mean, start giving it to chunks of irate fanboys holding their breath until 'their' version of a character comes back and before you know it we would have Hal Jordan back as Green Lantern. And nobody wants to live on THAT earth.
And Wally West
Me, I'm perfectly fine with singing, dancing Wally West from the teevee show, who somehow magically makes Iris less annoying just by standing in the same room. And his comic book counterpart, although we haven't had a lot of time to get to know him. Seems we will have more of him; he's clearly in the new Teen Titans.
Not the best hair-cut for guarding your secret identity, Wally.
I'm guessing Clark Kent gave you the ball cap.
This is good news. I don't want the resurgence of classic versions of characters to squeeze out the new more ethnically diverse cast of the DCU. Speaking of which...
Jackson Hyde
Jackson Hyde -- who had a brief stint as Aqualad somewhere during the last few reboots -- is back, black, and getting no slack. At least not from his mother, who provides the currently de-rigeur Parental Issue by being uncool with Jackson's having a boyfriend. I do appreciate DC making Hyde gay (no reason not to, since he has no backstory to the contrary). But I wish they would leave off with the "Anti-Gay Parent" schtick. Are there people still like this? Sure. But, increasingly we (and the DCU characters) live in a world where, well, being gay's not really a debatable issue. Characters like Mrs. Hyde are already seeming pretty dated, and that's going to get worse going forward. There are other ways of showing The Gay Struggle without a token condemnatory parent. Or just consider not showing Struggle at all and just showing The Gay; give that crazy idea a try, DC. To his credit, Jackson seems to just shrug it off with, "Um, yeah, whatever, Ma, that's quaintly old-school, but I'm just a tad more focused on the fact that I seem to have aquatic superpowers for no reason I can fathom and wait I think the fish are trying to tell me something,"

A Surface Custom
Yeah, I'll confess: I teared up when Aquaman gets down on one knee before Mera (and not to find her comb), and explains that "it's a surface custom". It sure is.
Now we know why DC seemed to have backpedaled on Aquaman having been married to Mera; it's so we can see them get married. Very nice one, DC. There really has never been a cooler romantic couple in all of comics. It's not just that they deserve to be happily married; WE deserve for them to get married. Who knows? Maybe she won't say yes, at least not right away. Mera's not one to do something like that lightly. But Arthur is a nice quiet Maine boy and it's exactly what he would do.
If she does say yes, Mera doesn't have a lot of gal pals to be bridesmaids; Batwoman maybe? I could really go for a full underwater wedding with Batwoman et al. wearing classic fishbowl helmets on their heads. Does Aquaman have any human relatives? Maybe a cousin named AJ?
Wonder Brother
Wonder Woman has a twin brother. I don't know any more about that and I don't need to. This idea is so ridiculous that I support it 100%. Sure, "previously unknown twin" is a trite soap opera twist. But long before 'separated at birth' was a trite soap opera twist it was a trite mythology twist. And Wonder Woman is, at heart, a figure of mythology. The time(s?) they gave Barry Allen a separated at birth twin was achingly stupid; it was just another way to create an anti-Flash for him to fight (because Flash writers almost never know what to do with the Flash if there's no anti-Flash for him to fight). But for Wonder Woman it makes a lot of sense. First of all, Zeus is her father and "Zeus fathers twins" is a pretty standard trope. Second, it's already been established that when the Amazons had male children that they didn't keep them on the island; no further explanation for his disappearance is needed. Third, Wonder Woman's dynasty has long needed a anti-distaff member; a missing brother will fit the bill rather nicely.

This is concept I could get behind. So to speak.
Baby Darkseid
Darkseid, who died, is now reincarnated as Superwoman's baby. Another "so ridiculous = 100% support from me".
I demand at least fifteen years of Baby Darkseid back-ups stories. Baby Darkseid versus Sugar 'n' Spike. Baby Darkseid meets WonderTot, Baby Batman, and Superbaby. Baby Darkseid. The Joker is hired as the party clown for Baby Darkseid's birthday. Baby Darkseid's omega-beams chase the neighbor's cat. Baby Darkseid's babysitter puts him in the microwave. Call me, DC!
Thunder-Home
Johnny Thunder is living in a nursing home. Again...that's all I need to know. The Flash story (Flash V2 #134) where Johnny Thunder, addled by senility, gives Jay Garrick his pen and tells him to look after his dog is one of the greatest DC stories ever told; it still makes me cry and gives me chills. [If I agree with these guys, it must be true.]
The fact that we know Johnny exists is the ONLY thing needed to bring back the Justice Society of America, because, while JT has always been a confused and incompetent half-wit, he also happens to have the ability to bring back the JSA with a single wish.
Joker(s) Wild
Apparently, there isn't a Joker; there are three of them. Again, another concept so ridiculous I support it, well, 300%. I'll take any out given from the corner into which Scott Snyder has painted the Clown Prince of Crime.
As long as this is one of them.
Nemo custodiebat
Apparently, we may be learning that the all-powerful being who's lost touch with all humanity and has a badly confused sense of reality who is responsible for screwing up the New52 universe by recreating it without the essentials of love and legacy is...
Dr. Manhattan.
Close enough!