I think The Blue Fairy gets a lot more blame than she should. I agree with AntBee that what happened with Rumpelstiltskin and Baelfire is not her fault. I do think she should have gotten involved more in that case–she basically let a fourteen year old handle the Dark One. True, he is his father, but she knows how far he steeped in dark magic he was. But he was a coward nonetheless. A lot of fans also blame her for with Regina, but I don’t think she deserves that blame, either.
My dislike for her started with Jiminy–she finally appears before him after forty years–how many years had he wished for help? Did she not see how miserable he was? Then it grew in Dreamy, when she told him that he and Nova couldn’t be together. True Love has been stated to be powerful, to be able to create happiness. Every character has said postive things about True Love, and I doubt that The Blue Fairy does not know how powerful it is, and yet she looks down on it. Nor does she allow Nova to make that choice–it is hers if she wants to give up her powers and her future as a Fairy Godmother.
It finally increased in The Stranger, when she lies to Snow White and Prince Charming, and then takes back the deal with Gepetto. That was messy way to deal with both parties.
I don’t think The Blue Fairy has everything planned–I think she is an example of the limitations of good magic. She only had one magic bean left, there was only one magical tree left, and she could not turn Gepetto’s parents back to human but she could help Jiminy look after Gepetto. She–for some reason–could not help the children in the wars, though perhaps the price would have been too high.