Honestly, I think you're the one overestimating the Wizarding public. The arguments from the wards aren't bad ones, necessarily, but they're technical ones. They won't play well. At best, they'll turn into conspiracy theories. Most of the public is going to look at the scene and see Lucius triumphant and Dumbledore with a black eye, and make the obvious conclusion.
It will still be basically the same in front of the Wizengamot. Having Hermione killed under his own protection means trouble for Dumbledore - it would be the second major security incident at Hogwarts in less than a month, and the first student killed in fifty years. It's not an impossible black eye for Dumbledore to overcome, and he could surely take it if necessary. But... Dumbledore doesn't have a compelling reason to take the hit. Framing Lucius is not an especially good motive, particularly considering that half of the Wizengamot cares not one whit about Hermione Granger's life or death. And, if he did want her dead, he could have avoided the fallout by sending her home over Spring Break with a snake in her trunk.
The technical argument... is still a bit above the Wizengamot. They might understand, "well, because of the wards this should have been impossible," but this will translate to "Lucius Malfoy found a way to trick Dumbledore's magic" and not "Hmm. Should Lucius Malfoy and his hired help really be in the same weight class as the Founders' wards?"
Finally, you're assuming that Lucius wants to clear his name. I don't think this makes very much sense, either. Sure, it's bad PR in many circles, but Lucius already has a horrible reputation, and I don't expect he'll be terribly concerned. On the other hand, killing a student right under Dumbledore's nose would be an excellent show of force, and it would impress people that he cares rather more about. It might be exactly what he needs, in fact - I imagine his credibility took quite a hit when Hermione Granger managed to escape punishment for an attempted assassination.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 88-89. The previous thread has passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: