I think everyone on some level is afraid it will get screwed up.
The question is, how badly? How badly COULD it get screwed up??
I propose we exorcise the jinx and explore the WORST POSSIBLE VERSIONS of a feature-film length Battle Angel adaptation! And I'll go first.

BATTLE ANGEL: THE MOVIE
Doctor John Ido, a warm, twinkly eyed fellow played by Bill Pullman is exploring the set of Blade Runner one day when he finds something mysterious in the rubble of the outskirts of town. It's a cute young girl! He takes her home, builds her an aesthetically pleasing body and introduces her to life in the dystopian future. "Alita" wants more from life, however, because she has angsty flashbacks of a time when she kicked ass! Who knew, she still can kick some ass! Alita becomes quite a proficient ass-kicking chick, working as a bounty hunter and taking down big stupid looking CGI imbeciles. Ido warns her about the danger, but she will not be dissuaded. Then one of them turns out to be more than she bargained on, a charismaless monster (voiced by Hugo Weaving?) maybe wearing like a black trenchcoat or something, who spouts trite nihilist bullshit, scares the shit out of everybody, and kills Doctor Ido in an emotionally wrenching scene reminiscent of the death of Mufasa in the Lion King. Alita is whupped bad and the townspeople turn on her. Disillusioned, she flees into the set of Mad Max: Beyond Thunderdome and takes on a job working for a shadowy government organization, kicking ass for The Man. There, she meets a big sexy dude, played by some guy from a popular tv show, who she initially dislikes but warms up to. Then they have a bitchin' steamy sex scene!! After which they decide to go back and save the city.
Twist!! The government organization opposes her! An old dude with a British accent tells her she "WILL be NEUTRALIZED!!" if she doesn't return to her duties. They send agents to stop her and her man, but they easily kick their asses, and trade sexy witty banter all the way. Alita and her man (who I forgot to mention will have an action movie name like "Hunter" or "Tex") return to the city, which has gone all to hell! They asskick their way in, and word spreads through the downtrodden denizens: ALITA IS BACK IN TOWN!!
They confront Hugo Weaving, who first says things like "do you really think that you're strong enough to beat me this time, little girl...?"
Alita and the hulkster are all like, "YEAH WE ARE!" But!!! Hugo Weaving has taken hostage some waif that Alita had a pleasant conversation with earlier in the film!!! (I'm thinking more Shumira than Koyomi here.) "Don't worry," her bf assures her, "I'll take care of the girl, you get Hugo Weaving!" Alita squares off with him, and they trade a couple taunts and trade blows, causing majorly impressive destruction special effects. Love interest then frees the girl but sustains a mortal wound! What gives!? The bad guy from the scrapyard was secretly a pawn of the shadowy government organization ALL ALONG?!? Dang! Alita is crying tears of rage, but Hugo Weaving has really got her on the ropes. JUST BEFORE HE CAN DEAL THE MORTAL BLOW, boyfriend appears out of nowhere and cheapshots the bad guy. Oh man is he pissed. He swats the wounded hero like a fly, but WHAT'S THIS?? Alita used the time that he bought her!! She is drawing upon some previously unknown well of power. SHE KICKS HIS ASS LEFT RIGHT AND SIDEWAYS! Take that, Hugo Weaving! The government agency is repulsed. The waif gives Alita a great big hug. Lo and behold, her boyfriend's all right! Yay!! Everyone in the city embraces her as their champion once more, and now Butch and Alita can live happily ever.
....UNTIL THE SEQUEL!!! COUNTERATTACK OF THE SHADOWY GOVERNMENT AGENCY! SHINY, COOL NEW TECHNOLOGY! ORIGIN STORY EXPLORED: A BEVVY OF BEAUTIFUL ASS-KICKING WARRION WOMEN!! RUMBLE IN THE WASTELAND! RUMBLE IN SPACE!! (Rumble from my lower intestine.) Coming Memorial Day Weekend, 20XX.
(Actually, this is kind of exactly what I'm thinking the Cameron version will be. Any other dystopic visions...?)