Part of me says I should bow to your greater knowledge, except that I have done it myself and I know lots of others that have too - in fact very few people use lawyers for this. MOS - you see the ones who unravel, not the gamut as the rest of us do.
I got an order, with no specialist input, dismissing all claims that either of us had against the other. I did it with the help and support of the court. I filled in the forms, went to the court, and the clerk said she would get the DJ to check it, which he did, and it was done. The boxes to tick included whether I wanted all claims dismissed, only claims on capital, did I want to include the pension, etc.
The courts are genuinely helpful to litigants in person, (whereas they enjoy tormenting lawyers) and since the OP is aware of the need for an order dismissing all claims, you are, in effect, paying for about 50 words of standard wording plus all the consultation time that the lawyer is obliged to insist upon because they have their own professional indemnity insurance to think of, and they are not allowed to just draft the agreement, they have to check all the circumstances and advise on whether the client is doing the right thing. I'm guessing two hours or thereabouts as a minimum? Probably a £500 bill with the VAT. And you won't find a lawyer to advise both of them, so they really should both have one, etc...
I understand that with your lawyer's hat on you find it hard to accept that it can be done without a lawyer, but with mine still firmly in place, I can. In many ways you are looking at this the way Health and Safety is looked at sometimes. If you only look at the risks, you would never do anything. Crossing a road is a risk. Getting on a plane is a risk. Meeting someone new is a risk. Using an electric hairdryer is a risk. Eating a cake or a sandwich or an apple is a risk. They are all risks, and they all bring benefits. We balance them out and make decisions.
Yes, there is a risk - but it is very small because this is very straightforward and the courts do seek to ensure that the intentions of litigants in person are put into effect. The benefit is that you save money that is probably better spent elsewhere, and you don't upset the applecart of a hitherto amicable divorce. Equally there is a risk that a lawyer would get it wrong - and then you are in the hands of another to sort that out, and so on. You can't eliminate risk, you can only weigh it and balance it against what you gain.