Yawn. Conley Woods has an article today where he assesses her and actually thinks she's pretty good. I don't see it. The most recent planeswalker printed is Ral Zarek, who is also four mana and gives you a Lightning Bolt for -3. That's nice value. Ping player and creature for 1? No thank you. And the zero ability means you're not playing anything on curve. If you untap with her, her value goes up substantially, but the turn she comes into play she is very weak.
I know some people were hoping for a 3-mana Chandra, and also a playable one. Here would be my initial cut (click to enlarge):
Her loyalty equals her casting cost, which is a good sign. Her plus ability is aggressive, as red should be. It synergizes with aggressive cards like Hellrider and gives you a dude as a possible sac outlet or excellent trade target. If you can somehow copy it via populate or another mechanic, you've got a blocker to protect her, but for the most part it's a balanced, standalone ability that works with red's flavor.
Her minus two is a solid, if unexciting, shock. If Zarek gets a bolt, surely Chandra should at least get a Shock. Like Liliana of the Veil's -2, it's potential immediate protection, but puts her at a very vulnerable 1. Seems like a decent tradeoff.
If this Chandra's flavor is spawning elementals, and if her +1 makes little guys, why not have her ultimate scorch everything and make Ball Lightnings out of the results? This last one should probably be tuned. Maybe it shouldn't do 6 to each player. Probably the elementals should be exiled at end of turn. But you get the idea. This is the kind of ability both playwise and flavorwise that I want to see on a Planeswalker. You probably win the game, and it's hyperaggressive, but a single Profit/Loss or Electrickery will wipe all your new dudes, so it's not necessarily and insta-win.
Unfortunately we're stuck with the clunky new Chandra. I don't think she's very good, except in Limited, which is what I most play. I could be wrong, but I don't think she'll see play in Standard.