My main issue with her status as a "main character" is that she's not actually important to the plot of the story. There are a few cases where Sakura is filling a role that supports the main characters - but the same can be said of characters like Shikamaru - who are not main characters.
Her personal character has almost zero plot significance.
Though that will likely be changing. Sakura will sacrifice herself to prevent Naruto and Sasuke from killing each other:
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Over exaggerate?
Do you know what the word: "Exaggerate" means? Or do I need to visit the Automatic Teller Machine (ATM) Machine to buy you a dictionary?
Or am I making enormously large, mountainous mountains out of mole-hills?
Sakura still loves Sasuke - and is still committed to him.
The difference between her and Karin is that Sakura is also committed to an idea - to Team Seven and the village it stands for. Which is why the wind that blows the Sakura is the wind that will move Sasuke.
The reason people like myself don't really hold Sakura in very high regard as far as a valid team member is because of the rarity of events like her kick-assery in the Forest of Death. That was an ingenius tactical ploy with her use of the substitution Jutsu. She set up the pattern that she'd only substitute away, which (at least in real life) would have meant fewer kunai would be thrown at her (why throw a bunch at something that's just going to poof away?) - giving her a way to influence the amount of attrition she had to accept when she finally launched her attack.
But... that character doesn't make an appearance at the Tenchi Bridge. It doesn't make an appearance in Orochimaru's hideout. It doesn't appear during Pain's invasion.
That's why I wouldn't take her on a forward operating team. I don't know whether she's going to end up being a bad ass or whether she's going to end up being a damsel in distress. Unfortunately, her history of being a bad-ass tends to be when she's the only one left standing.
And, in most of those cases - everyone would still be up and standing if she'd run "badass.exe" from the get-go.
All of the character judgments on Sakura are not really relevant to the point that Sakura's character holds almost no plot significance. The most plot-relevant part she will play is resolving the issue between Naruto and Sasuke without those two having to forfeit their lives. I highly suspect that will cost her the life she has.