There wouldn't be much of a redemption arc if she hadn't fouled up first. And obviously you have access to material which I haven't read.
All that's from Blood Rites and Changes -- she had Thomas and left when he was 5, so she was with Lord Raith for that long at the very least, and Ebenezer describes a meeting where she was trying to get Ebenezer in on a scheme she was concocting that involved both Lord Raith and Arianna.
And Ebenezer is pretty clear that she struck out on her own at least partly out of rebellion against him, her father, personally.
Sometimes winning is just not losing. So if she had two years with a man that loved her, that was two years she wouldn't have had otherwise. As to if she had planned for Raith to become Lara's sock puppet, it misses the point. She couldn't know how it would turn out, but had she failed as Eb had, Lara would have never had the chance. And as long as Thomas could stay alive Raith was prime for a back stab from someone. In a sense, if indeed JB is thinking this way, it was only a matter of time. Since Maggie was a mortal she was born to die, Raith could have lived forever. Who lost more? YMMV.
I'm not denying that the Death Curse she placed on him was clever -- it was, as defiant last-attacks go, pretty brilliant, and was probably only possible because of their, ahem, intimate familiarity with one another.
I'm just saying it was probably more of a final "F*CK YOU" than it was looking into his future defeat. But that's my read on Maggie -- I get the sense that she wasn't really that smart about things until maybe right toward the end. Clever, sure. Powerful, sure. But she made a lot of really, really bad decisions that she should have known better about.
Well when JB actually has Harry doing that I might buy in. Up to Skin Game Harry has treated people poorly. He basically threw Molly under the bus in Changes. And JB then wrote Ghost Story just to point it out so we didn't miss it. Then he reinforced it by having Mab point it out to Harry in Cold Days. In a number of ways Harry is much the same way as you have described his mother. He treats with the fae, has Lara Raith as an ally(evil vampire). Sponsored Marcone as a free holding Lord(murdering crime lord). And made a deal with a so called evil fairy when his daughter was at risk.
Right, and as you say, he learned a hard lesson about that. The difference is, he ... well, I guess he didn't learn it
before he died, per se, but he got sent back for another go anyway.
The way I look at the difference between Harry and Maggie Sr. is, when Harry does those things, we see his inner monologue about how it's a tough choice he has to make, and it's the lesser of a variable number of evils. The sense I've gotten about Maggie Sr. is more that she went into things with the attitude of, "I can handle this, because I'm just that smart and awesome." Now, granted, we haven't seen into her head and only have second-hand accounts, but like I said, that's the sense I've gotten from the evidence we've seen.
And as Peregrine pointed out, Uriel makes it explicit.
And it's not just about what Harry, personally, does. Look at the folks he calls "good people," like the Carpenters and Murphy. How many times has Harry survived because one of his mortal friends stood up and decided to Do The Right Thing?
How many lives were saved just from Butters squaring off with Cassius?