Oh, this old argument.
I watched the 2006-2010 quad quite closely and I would say that the real cause of the point gap at the 2010 Olympics was not the rules regarding downgrades (which were more favorable to Mao in 2009-2010 than 2007-2008 -- judges couldn't see if the < symbol was given and could still award +GOE) or the judging, but Mao's perplexing strategy regarding jump layout, questionable choreographic choices, and overall physical condition that caused her to not execute to the best of her (previous) ability. On the other hand, Yuna Kim was at the peak of her ability, upgraded her jump combinations, added jump transitions for even more +GOE, had two crowd-pleasing and judge-pleasing programs, and executed flawlessly.
Mao 2006-2008 made way better choices in jump layout/choreography/transitions and was in better condition (at least in terms of jump consistency) than Mao 2009-2010. Any of her SP programs from 2006-2009 were better than the recycled Masquerade choice in 2009-2010. Either of her FS programs from 2006-2008 were better than Bells of Moscow. Her jump layouts were optimized and she had fewer meltdowns, in particular the one 3A / 2 triple/triple layout from 2007-2008; the choreography and transitions were more complex then as well. She won every competition except GPF in 2007-2008, and then split with the coach and discarded the jump layouts that got her the best results; unquestionably, the results for 2008-2010 were inferior to the 2006-2008 period. Tarasova choreographed nice SPs (Ladies in Lavender) and exhibitions for her but the music choice and FS choreography in 2008-2010 were not good.
If you look at Mao's 2008 Four Continents FS (or 2008 Worlds FS, minus the triple axel attempt and fall) and 2010 Olympics FS and watch them back to back, there's no comparison. She's faster, has more complex (and better) choreography and transitions, and her program is packed and yet well-balanced with the 3A, two 3/3s, and even a 2A towards the very end.
The most disappointing thing about the 2010 Olympics is not the point gap, but rather that Mao didn't bring her best to it -- not her best programs, not the best jump strategy, and not her best execution. The point gap is because Mao wasn't at her best and Yuna was. The closest thing we got to Mao's best versus Yuna at her very best during this quad was probably the 2007-2008 GPF. Both skaters made bizarre mistakes but both were healthy; Yuna didn't have her best programs of her career but skated with incredible speed and precision for the elements she did execute; Mao did have one of her best combination of programs and she hit her 3A and 3/3s (though the quality wasn't perfect; she had some two-footed landings). That was a more interesting and close competition than the 2010 Olympics. Some folks seem to have expected the 2010 Olympics to be like 2008 Worlds, an extremely close competition between Mao and Yuna when Mao was at her peak but Yuna was not; she was competing extremely injured and with some of her weaker programs.
As for Joannie Rochette, regardless of the emotional context, I think she deserved her bronze. Her SP jump layout is still curious to me -- for someone with a reputation as a strong jumper and who had previously done 3Lz/3T and landed quads in practice, I don't know why she couldn't at least do a 3T/3T and 3Lz in the SP, boosting her base value a bit. She skipped an entire 2A in the FS and so don't think she merits much more.
Mirai Nagasu was wonderful and delivered a very memorable FS. It didn't win a medal, but she won a lot of fans that night. And she could've leveraged that momentum into a world medal later...but she didn't.