Gotham Knights looks alright to me, the coop makes perfect sense, since they've been toying with the idea of dual combat since Arkham City, the numbers/levels thing seems superfluous, but of course we'll have to see how it's balanced out, although the idea of bullet sponges in a free flow game sound atrocious.
These Arkham games were getting really samey and tiring after 4 entries, so they did need something significant to shake things up, hopefully the coop it's it.
Also i'm not a Batman expert, but all the characters look too similar in terms of gameplay, although Batgirl and Robin are probably the most fun to use (usually their nimble characters were more fun than Batman, see Harley and Cat Woman in City/Knight).
Suicide Squad looks like it has some impressive graphics (assuming the trailer is in-engine) but i found the banter immediately insufferable, and i still don't understand what type of game it's supposed to be.
Speaking of Batman hero shooters though, they already had one such title, remember?
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