The role of liaison officer is to serve as a communications tool for climbing teams and to monitor activity on the mountains to ensure that everything is done according to regulation and in a safe manner. They are also there to coordinate rescue operations and assist in helping sick or injured climbers getting back to Kathmandu where they can be treated. But most of those duties are falling on the guiding companies, who coordinate those efforts themselves.
Nepali law states that an LO must be assigned to every climbing team heading out to a mountain, and that the liaison officer accompany that team to BC, where they will stay for the duration of the expedition. Unfortunately that isn't happening, despite the fact that teams pay $2000 in fees to pay for the LO's services. That money seems to be getting pocketed, with no real value being added for the climbers in anyway.
With several high profile disasters on Everest and other mountains in recent years, the Nepali government has vowed to make climbing in their country safer. Despite those claims however, there doesn't seem to be any significant strides being made in this area. The fact that after two deadly avalanches on Everest in 2014 and 2015 there still hasn't been a change in operations is quite telling. 80% of the LO's report that they've actually been to the mountains, although records indicate that they have never stepped foot out of Kathmandu.
As far as expedition leaders go, they have found that there is no sense in complaining or calling out a specific LO. If they do, they suddenly find it much more difficult to obtain climbing permits or they are charged fines for minor rules infractions which may or may not actually be true. In other words, if you report on the liaison officers you'll find working in Nepal is a much more difficult proposition than you first imagined.
In Nepal, the job of being a liaison officer carries some level of prestige, and most get appointed to the position as a political favor or after providing some level of service to the Prime Minister or other government officials. Because of the stature of the position, a culture has permeated throughout the LO's that allows them to get away with not doing their jobs, but still collecting the fees paid by climbers. For this to change, the Nepali government is going to have to force them to start following the letter of the law and reporting for duty as expected. Until then, Nepal can talk all it wants about how it is going to improve safety in the mountains. Having good communications and someone who actually does the job they are assigned would be good start.