Re: So I took a Judo class today...
Curious from what experience you are drawing your conclusions from on jiu jitsu? I think it would really depend on the jiujustsu system you are talking about.
I believe Kano derived Judo from jiujutsu and alot of that was based on politics and philosophical differences based on the time and climate in Japan.
It is possible that Kano improved upon Jiujutsu, but since it would essentially be a derivative, I find it hard to believe that it would be more combat effective.
Diato Ryu is a form of jiu jutsu, BJJ is a form of Jiu justsu...I do not put them in the same category as aikido really if you look at it that way.
I used to think that competition ALWAYS watered down the combat effectiveness of a system. Now I think that it is immaterial. Some competition is good. The problem with it is perspective. If you focus solely on the "game" you may not gain all the "combat" aspects of the art.
That said, I am skilled enough at this stage to be able to do both and recognize the difference between the game and reality, so I don't think it hurts at all. I think there are some very good skills you get out of competition. You just have to be careful and have a good instructor that knows the difference.
I know from my karate that I was taught the first couple of years to turn my fist all the way over and expose my back cause you got more distance and could "score points" witth less risk for your opponent to "hit" you. Not to pick on TKD guys, but I have worked with many that really do not understand "real hitting and kicking" and make mistakes that would get them in trouble in a real fight. Usually they are beginners. Once you get up in rank and gain experience, you can figure it out, and the skills you learned about distance, speed, and timig are equally important.
Again, I think it is all about perspective and balance.