That's the easy way out. There's no REASON for them to do it this way and it would be the expected thing to do, but I am betting they'll do it, and just have Ahsoka die "senselessly" and have Anakin "blame himself" and be haunted by it.
If they go that route it would be nice if it really was all Anakin's fault, but since this is a kid's show (even though they try to make it "edgy" at times) it probably literally won't be Anakin's fault, but he'll say it's his fault anyway, and carry it inside him. Like she'll make some "cocky" decision based on what she learned from her "Skyguy" and get killed.
What would make it even more silly (I know, I'm just ranting here) is to have Ahsoka die in battle with Ventress, and then have Anakin kill her in vengeance (AGAIN). End the last episode with him telling Obi-Wan "don't ever mention her again."
Frankly though, I really don't care what happens to any of the characters in the new series. As far as I'm concerned it is a separate story line from the movies. Sadly, due to expectations (and the track record thus far with Prequel stuff), none of the movie characters can have anything meaningful or lasting happen to them. All will be forgotten from the "leap" at the end of the series to Episode III.
On the other hand Lucas' penchant for leaving loose ends would make it feasible that he'd just have Ahsoka go away (and not die) and leave it up to the imagination. I wouldn't have a problem with that, and in fact it would be nice to see. Of course if that happens you know they'll have people demanding they finish the story (and writers will see more money to be made) by putting her into a novel or comic or two to "finish the story."
All the EU creators seem to suffer anymore from the two tendencies: 1) Make it just like the movies because you're unimaginative or afraid of taking risks, 2) Make it as different from the movies as possible just to be different (and end up losing that elusive "Star Wars feel" or being silly).
It seems if they had wanted to make it all consistent, it would be for Lucas to lead by example and have some serious continuity people on hand throughout. Leeland Chee seems more like he just sits back and when a source comes out, gives his own explanation for it after the fact (prompted by whatever Lucas is feeling at the moment). They fire off a new story without really checking to see what's going on. If it sounds cool, it doesn't matter what it conflicts with. That's my hunch, anyway.