Can Aikido beat BJJ?
Can my sandan beat your sandan?
Not really sure why you went back through this thread and pulled out this one quote of mine...but I'll roll with it.
I only brought up the sandan rank because someone else was using it as a standard bearer for effectiveness in Aikido (along with a bunch of other crap that I don't remember, and don't care enough to look for it).
Personally, I think rank in any art that does not base its belt system on being able to perform well in "live" (rolling to submission, striking to TKO or KO, Ippon throw, etc.) competition means very little in regards to effectiveness of the practitioner in application.
Let's take BJJ for example since it seems popular to dogpile on. If I go up to any brown belt in almost any BJJ gym in the world, I know that the guy is going to be trouble on the ground; serious trouble. He should be able to give anyone difficulties. I know this because the guy obtained his rank by demonstrating that he is effective in a resistant, "live" environment.
Aikido (with Tomiki and its ilk being the exception) rank can be based on whatever. It's completely subjective and is entirely up to the instructor. I would think most people have met students in Aikido who are brown belts or shodans, not because of their talents or skill, but based upon the fact that they've just hung around for six or seven years. In my experience with BJJ thus far, I have yet to encounter this type of situation.
The only thing that approaches it is in BJJ tourneys where there is usually a "Masters" or "Executive" division for people 40 or 50+. And it's there because people know that even though someone might be a brown belt in BJJ at 55, they can't compete with a brown belt at 25, just based on sheer physicality. Whereas in Aikido, somehow the older you are...the better you get at it?
So whether someone is a 4 kyu or 2nd dan in Aikido, doesn't really make much of a difference to me. Again, (and I think lots of Aikido people miss this point and just get hung up on BJJ) it's not that BJJ and it's techniques are better or anything. Someone trained in BJJ, wrestling, boxing, etc. is more likely to be effective because they train and compete in a "alive" environment where they regularly encounter resistance and learn how to overcome it. In cooperative practice, you are never going to have that opportunity.