Errr - pardon? What exactly do lawyers have to do with solo diving? If you do a solo dive and drown yourself, what is the cause of action? And who sues who?
As for the topic: It's been said by others better than I can put it, but: if you want to dive solo, go on & do it. If you think you need a course / cert card / book / long internet discussion on the topic, you shouldn't be diving solo. The agencies are right to discourage it "officially".
Solo diving and lawyers are intimately connected.
Why do you think some dive boat operators won't let people dive solo?
Why do you think dive agencies bash solo diving?
FEAR OF BEING SUED. The deceased family can and will sue everyone involved, from the dive op, to the dive shop, to the dive boat and even other people on the boat who were not involved. The lawyers will poke around and try to find anyone with deep pockets or a hefty liability policy which they can suck dry to make themselves rich.
In actuality is really has nothing to do with solo diving per se. The lawyers will use the opportunity of a solo diver's death to find a way to suck cash from someone else. The lawyers aren't there because they feel badly for the dead guy. The lawyers are there to use someone's death to make money.
If there weren't any lawyers, solo diving would be a non-issue.
Back to the OP's question: Do you think in the future that agencies should stop teaching how evil solo is?
Answer: It won't happen as long as there are lawyers.