I'm sure there are other great writers out there who would do great work, but Andreyko sticks out because his Manhunter--also about a kick-ass superheroine named Kate who palled around with Cameron Chase and the DEO--rates up there with James Robinson's Starman in terms of consistency of vision and overall quality.
He's also a guy who has the respect of his peers; terrific artists like Jesus Saiz and Brad Walker have worked with him in the past, and both Walker and Matthew Dow Smith spoke up on his behalf on social media shortly after he was appointed to the Batwoman job.
Why should you be excited to see Andreyko taking over Batwoman, even if you're not excited by the way he got there? Read on...
He can play the game.
One of the things that really made Manhunter stick out on the stands was Andreyko's ability to cleverly weave a great story into the intricate editorial demands of life in the DC Universe.
That's a skillset he's going to need going into Batwoman, as DC have hinted they want the series to connect more directly and intricately into Batman's corner of the DCU.
Kate Spencer's title was, very much like Batwoman's, a book that saw her generally divided from the DC Universe at large for much of the run, existing in her own little corner. But DC and Marvel don't like that anymore; they want everything to revolve around the superheroics rather than the humanity, and to emphasize the interconnected nature of their fictional universes.
How'd he work around it? By finding obscure bits of DC mythology to which he could connect Kate and her personal history and mythology. The issue that explained where her costume alone was enough continuity porn to put even Geoff Johns to shame, and yet the book remained very easy to jump onto because all of that continuity was built into the background, where it wouldn't interfere with any given issue.
So...yeah. In an age of editorial meddling, Andreyko has a history of making that kind of thing work for the story in cool and unexpected ways.
He's not really new in town
This is a guy who's written in Gotham before; sure, his most notable DC title is Manhunter, which took place in the real-world city of Los Angeles...but toward the end of that run, he was tasked with moving the character and her adventures to Gotham.
He's also had a history with Nightwing and the Gotham City Sirens title, as well as writing Barbara Gordon back when she was Oracle and Manhunter was part of the Birds of Prey.
He's great with bad-ass female characters--and not just the obvious ones.
Not only is Andreyko great at writing female heroes, but his heroines don't have to act larger than life and obviously bad-ass in order to resonate. He's able to run the gamut from supervillains to government agents to Angry Young Women to the matronly, underestimated character.
That's great, because one of the things you'll notice pretty often in superhero comics is that a female character often has to act like Wolverine to be taken seriously; she's either a delicate flower or the baddest badass in the room, who'll emasculate you just for questioning that fact. And while that might be a bit less condescending than the "little lady" variety, it's still not an accurate reflection of the breadth of female personalities. Andreyko has written a much wider variety than that, and generally received good marks at it, too.
He knows Chase and the DEO
As you can see in the top image, Cameron Chase plays a role in Batwoman--so does the DEO, as Kate is a somewhat reluctant employee of Director Bones from time to time.
That's pretty much the same dynamic that Andreyko had for Kate Spencer, who was Chase's college roommate and whose identity was quickly sussed out by Chase and the DEO, who then periodically recruited her to help them out.
In other words, Andreyko has already written almost exactly the same dynamic that he's being asked to write here with those characters, and he did it pretty well. That seems promising...
He writes LGBT characters really well
Back when he was on Manhunter, we spoke about his gay characters, and he told me that his "trick," which was really not a trick at all, was to just write them like he would anyone else, except that their significant other wouldn't look like readers might expect going in.
And, yeah, along the way he infused a believable and relatable cast of characters, including some homosexuals who never felt like token additions. That's something that Batwoman has done--used LGBT relationships as just...relationships, without having A Very Special Issue related to Kate's sexuality or anything like that. It's what made the book a hit among an audience clamoring for gay characters to be presented in a way that's a little more sophisticated than the X-Men's publicity wedding.
That's something that DC Co-Publisher Dan DiDio is apparently quite proud of, as all weekend long he's been beating that drum: "What other publisher has that level of commitment to an LGBT character?" He has asked a handful of times (I'm paraphrasing). Well, even as it appears Kate's role will be to be rolled into the Batman family more than ever before (and therefore probably lose a bit of what makes the book unique in the eyes of many readers), it seems that supporting her character development is something they're still shooting for--even if they won't do it at the pace the readers might have hoped.