Wasn't aware of the Supergirl stuff. That show never really enticed me to watch - was it any good? Did they handle it well? I've always found Superman, iconic as he is, to be a bit boring due to his abilities. (Though I absolutely love the Death of Superman comic storyline - first graphic novel I ever read). I wonder - Supergirl is from the Superman Returns universe? Will we see Routh, who works/worked for CW appear as Supes? That'd be convenient and also double as some stunt casting and would get a little press (not as much as if they got Cavill but let's be real).
Routh is Atom in Legends of Tomorrow. Tyler Hoechlin has been cast as Supes (whoever he is).
CBS had the first season of Supergirl, and it's alright. Kinda similar to Flash's first season where Starlabs
help Barry harness his powers, except it's about pretending to be normal with help from Jimmy Olsen.
huggybear - I could absolutely see it being Nyssa vs Malcolm actually. That's a good shout. That would perhaps be more of a shadow-war than the Atlantean-Amazon wars but I think they could absolutely make it fit. And the guerilla type war with a lot of civilian casualties caused by those two factions would probably fit really well into a more real-world feel (real world in the sense that Flash Tv show is a bit less fantastic than the DC comics universe). It'd also be a lot easier to do on the TV show budget.
I had two trains of thought on this matter. Firstly they could use two other characters that I'd consider pretty core JL members - Martian Manhunter and Green Lantern. But we all know they won't do GL. And I think J'onn looks a bit too weird. Your idea definitely seems more likely than what I was thinking.
Second - have a Mirakuru soldier army vs the League or Damien Dahrk or the like. So Deathstroke would be a major villain. It gives him an army of super soliders which fits the bill and let's us have more Slade. I'd love some more Manu Bennett. Flash wasn't Flash when Deathstroke was trying his sh*t so if Ollie wasn't about to stop him due to Barry messing with time then maybe he could have succeeded.
They could replace Cybord with either GL or Martian Manhunter but I don't see that.
J'onn J'onnz is in Supergirl, so they could use him if they wanted, and Vandal Savage is in Legends of Tomorrow, so they could use him for a super army of some kind of bad guys
I'm wondering if we will see the Flashpoint universe get it's own little arc in the other shows? I mean, will Arrow S5 just be like Arrow S5 in the universe we know with no direct effects from Flashpoint or will at least a portion of it be showing the team as they'd be in the Flashpoint universe (assuming they are even alive)?
I still think that they'll do the ending of Flashpoint but with Ollie getting a letter from Robert. And I think that'll be stupid. Batman's relationship with his folks is nothing like Ollie's and it'll lose all it's meaning.
I've recently been re-reading a lot of my Green Arrow comics. I'm in two minds about some of the choices on the TV show. In one respect, I want them to stay true to the character and I like when they do stories similar to comic book ones I've read. But I've read the comics so I also want them to try and do new things. I put up with Olicity, possibly partly because EBK is drop dead gorgeous and I find her character appealing also. But I think they could have done a lot better with the treatment of Black Canary and the romance between her and Ollie. This, apparently, is a huge sticking point for a lot of fans of the show. In the end, they screwed up GA/BC as a couple before S1. I thought Amell and Cassidy had really poor chemistry together and I don't think it would have worked. I also think they wasted Roy Harper. And I really want them to bring Mia in. The GA graphic novels she's in are among my favourites and I think she has a rather compelling storyline.
Colton Haynes left Arrow because he struggled with the anxiety of being outed by the media, so we could see him come back as Red Arrow from Earth-2 or Earth-3.
Mia Dearden won't show up because it's an alias Thea uses when she travels with Merlyn for her training.