The first issue is the breakdown in trust. The relationship between a divorce lawyer and their client is a tricky one. It is like a microcosm of a marriage itself: you have to believe what the other person tells you and trust that they are looking out for your best interests. Once a client has an idea in their head that I am not to be trusted, the relationship suddenly gets a bit chilly. This may work for some attorneys, but is generally something I find not conducive to a good relationship.
The next issue is the increase in fees. Clients hearing war stories from their friends usually leads to longer phone calls and emails where I have to explain to the client (1) what worked in your friend's case may not work here, and (2) here is why it won't work. When there is trust, brief explanations of strategy suffice; when there is not trust, it leads to long drawn out explanations of minutiae. Do not take this to mean I prefer keeping clients in the dark; far from it. However, sometimes the explanation can cost more than the answer when there is not trust about the handling of a case.
Lower satisfaction is the last concern. There is an old saying in divorce law: "if nobody is happy, it's probably a reasonable result." Divorce is obviously not easy. Sometimes, however, seeing it is a win-loss matter based on a whole different game can lead to dissatisfaction that lingers years after the divorce ends. I say that divorces are like snowflakes: each one is different. Setting an unreasonable goal in a divorce is a sure road to dissatisfaction. I see it as the equivalent of setting a goal of fitting a square peg into a round hole, then beating yourself up for not being able to get the square peg in the hole. Setting goals that fit your situation lead to a better feeling of resolution, allowing the client to feel like they can move on quicker.