It's a better than average writing job for Judd Winick. If you're a WInick hater, be prepared to be surprised... He justifies his paycheck here.
The film is really not based on any specific comics... Much like Superman/Doomsday, it takes specific subplots and wraps a new story around ideas and concepts many people are familiar with. If you haven't read the original comics, good for you... This is actually written better and makes more sense than the convoluted junk that's been floating around DC for over 20 years now!

I guess having to work a story into 75 minutes of film instead of writing a six-issue story arc helped Winick focus on getting TO THE POINT. There was no time for him to politicize and do the knee-jerk bully pulpiting he has a tendency to do.
Production design was nice on the film even though I generally don't care for the character design on this and other recent works like Green Lantern: First Flight. A return to more stylized designs like Bruce Timm's would be nice.
This is probably the best Batman animated film since Sub-Zero but I still had basic problems with it...
... In many ways, this should have been rated "R." It's extremely violent, and there are scenes of teenaged Robin getting the snot beaten out of him by a crowbar-wielding Joker. While I don't find this Joker as annoying as the (IMHO) overhyped Heath Ledger Joker, it's still very disturbing to watch and realize this was a character created for a comic that was intended to be read by 8-10 year-old boys.
I've read those first Joker appearances in 1940/1941, and there were good reasons to tone the character down immediately afterwards. It wasn't until the 1970s that Joker reverted back to the ghoul he was in the first few Batman stories he appeared in.
In many ways, this is the Joker that today's Batman fans want. Great... if you're 25 years or older. Not so good if the audience is younger than that.
The other disturbing character is one supposedly killed off 22 years ago but inexplicably brought back by DC a few years back. Originally, Jeph Loeb wanted to bring "him" back in a Batman story arc called "Hush" but DC editorial at the time wouldn't let him. Winick got the okay to do this a few years later and it was one of the lamest and most contrived character revivals in recent history. At least the mechanism Winick uses in the film is nowhere near as dumb as "punching walls through time and space." The film revival mechanism actually would have worked better in the original comics, too, if anybody had been bright enough to approach it that way!
This is definitely not a family film and anybody with young kids should practice responsibility and lock the film up-and-away from them or not buy it.
********
I have less reservations with Jonah Hex.
Hex is SUPPOSED to be an adult character. The short's probably better than the live-action film which died quickly and is another solid entry in the DC Shorts library.
For me, it's a toss-up between whether this or the Spectre short was better. They're both excellent shorts and show a lot of Japanese influence in basic animation and aspects of design.
These shorts just couldn't be done completely in North America. It would eat up the budgets WB put aside for the films -- Yes, the shorts would cost at least as much as the 75-minute films if they were completely done in the the US or Canada!
There's excellent voice talent in both the Hex short and Batman/Red Hood.
As far as I'm concerned, Bruce Greenwood could take over for Kevin Conroy or alternate the Batman every other film with Conroy from now on... He's definitely got the vocal quality for Batman and might be a good consideration for a special Batman story. Thomas Jane was also effective as Jonah Hex. DiMaggio is serviceable as The Joker but I still prefer Mark Hamill and the actor who performs The Joker on Batman: The Brave and the Bold.