Just visited the site because of a thread started on a judo site (possibly to create conflict between judo and aikido practitioners), and noted this thread. Just a quick point from an old time judo and wrestling instructor who also teaches at a MMA club: no one does pure judo (or pure BJJ or pure boxing or pure aikido or pure anything) in MMA. MMA is a sport, and to do well in it you're going to have a good base in many aspects of grappling, throwing, and striking - no traditional art covers it.
So while the most successful judoka in MMA is Fedor Emelianko (he was on the Russian national judo team and placed in several international judo tournaments, giving him much better judo credentials than say Karo), judo/sambo is clearly only one part of what he does in MMA. The same is true for Karo and everyone else mentioned - they all cross train. Most discussions of judo (or any style) in MMA are pointless because in fact its all become part of the general toolkit, and the people chosen as "representatives" of a style are in fact representatives of many styles.
In the particular case of Yoshida vs Gardner, you had two individuals competing, neither of which should have been in the ring. Yoshida won his Olympic gold in 1992 fighting under 173 pounds, by the time he started MMA he was 50 pounds overweight and unable to win in international judo (possibly simply because he was in fact 50 pounds overweight and correspondingly out of shape). Rulon Gardner won in the super heavy (over 265 pound( division in 2000, but was too gentle a soul to become effective in the striking, which is why he never fought again in MMA - he didn't like punching people, and you cannot compete in MMA without doing so at least some of the time.
As for aikido and judo, they're more complimentary than anything else, in that they have similar principles working on different ranges - aikido at arms length and more, judo at clinching range. Both have their pluses and minuses, but if I were to teach someone self-defense I wouldn't start with either of them (or any unarmed art). Basic street sense (situations to avoid), and then if necessary weapons training is far more practical and easy to pick up for anyone. A person can be effective with a gun, knife, or stick in a day, and if we're talking about real self-defense rather than just going to the bar to pick fights, that is what they should be looking at.
We regularly tell people who start MMA, judo or wrestling for self-defense that since at least local police statistics say most self-defense situations involve multiple armed attackers (knives or firearms being most common) that they'd be much better off learning to use weapons than any unarmed art. If you can seriously avoid being swarmed or shot by five or more fit young men with knives, guns and baseball bats, you should be playing in the NFL. Otherwise you'll need a weapon yourself - and even then only if there is no other option. It only takes one bullet to change a successful defense into an untimely funeral.
Finally, though aikido isn't mentioned much in either judo or MMA circles (no more than I expect judo is mentioned in aikido circles), when it comes up its usually with respect for its footwork, posture, and wrist locks (which is all most of us know about it). The only place I've seen aikido put down as ineffective is on internet sites, and as always on the net its probably an attempt by trolls to create an argument.
Anyway, sorry for interfering with your thread, I just think much of the conflict between styles found in the net are artificial. I'll leave you in peace now.