The legal system should be accessible for all but there are several barriers which get in the way. The first is cost and this is not universal unique to the disability community. Good legal advice and action costs money which a lot of people with disabilities and everyday citizens do not have. If people don't have the money they probably won't take action.
Another form of action could be going to an enforcement body and filing a complaint. You may want to assess if this is an option and also if this will get the outcome that you desire.
There are communication issues for people that cannot talk or use sign language. While you can bring interpreters this means an extra person is involved with your legal affairs; get them to sign a non disclosure agreement. If you don't want to use your regular carer legal advocates may be available to help. Some professionals may be able to communicate with you alone. If there is a group of you that have this need; you may want to seek out a professional and train him/her up to communicate with people who have communication difficulties.
To an extent the above also applies to people that have difficulties understanding or reading. If you cannot read most legal representatives will read the document to you. If your lack of understanding is significant it may be time to get a power of attorney. You don't necessarily need one if you just have problems signing, consider a signing stamp.
If your stamp gets into the wrong hands it should be treated similarly to a stolen identity which means involving the police. It is possible that this could protect you from liabilities but you should check with a local lawyer first.
Unfortunately there are people that target people who experience disabilities to take advantage of them. You should always be wary of such behavior and try to protect yourself.
I know that I was not wanted to part of a jury. I think that this suited me at the time but I think that the justice system should be inclusive. A jury of peers should include people with disabilities
This could be problematic for cases involving victims with disabilities as a person that has a disability on the jury could be worthwhile.