This is a post from another forum by Sensei George Ledyard.
''There are really two reasons why Aikido doesn't have ground fighting of the sort that we see in Brazilian Jiu Jutsu and the like.
O-Sensei was once asked this question and he replied that "rolling around on the ground with another person is unseemly. That's why we have suwariwaza." Since an aspect oif Aikido is character development there is emphasis on elegance and posture etc. that may not be there in a purely fighting form.
But apart from that issue, Aikido, as refined as the practice has become, is an art that: 1) assumes that the opponent is armed and 2) is desigend for multiple attack.
People often completely misunderstand the nature of the attacks in Aikido. Why is there all that grabbing? No one fights that way they say. When I started doing police training I was dealing with the equivalent of the modern samurai. An officer is a walking weapons system with an entire array of weapons on his person. Often he is deploying or attempting to deploy one of those weapons. Guess what often happens when a subject wants to prevent that or even take a weapon away from an officer? He grabs the officer and / or the weapon. All that grabbing stuff starts to make perfect sense again.
As soon as you make the assumption that you and your opponent are armed, possibly with multiple weapons as the samurai was, Gracie style jiu jutsu makes no sense whatever. Poistions such as the mounted position simply give the opponent access to the weapons on your belt. Most of the "pins" in Aikido are not submission pins. The are designed to place an opponent in a position of disadvantage long enough to access a weapon an finish him. In older styels of Aikido ytou can see this symbolically represented by the final knife edged strike that occurs after the opponent is pinned.
As soon as you introduce the weapons element into the equation you can see that suwari waza is preferable in many ways to submission style grappling. All of the techniques that you can do standing are available to you, it is a position from which a weapon can be effectively deployed, and it allows for movement which is necessary in mutiple attack situations.
The last is the main and most important reason for no submission style grappling techiques in Aikido. The assumption in Aikido is that you are in a mutiple attacker situation. The emphasis is entirely on freedom of movement and postitioning. Most techniques have variations that allow the defender to use the attacker he is currently dealing with against the next on-coming attacker. Most techniques contain movement variations that not only allow you to strike or throw the current attacker but position yourself to effectively receive the next attack.
As soon as you assume that there are mutiple attackers many of the most effective submission fighting techniques become suicidal.
It is important, especially for Aikido practicioners themselves, to remember that the art they practice in the dojo is a very refined practice designed to isolate and teach a very complex set of principles. It is not, in its basic form, the real fighting version of the art. People from outside the art misunderstand what is going on because they only see the basic practice. These days, many Aikido practicioners themselves do not really understand the application of the techiques they are studying.''
I thought it was a very well put post. Im sick of people on this forum saying this martial art is better than that one. If one was the best everyone would do it.