Originally, L&P had planned to alternate between Sophia and Liam for one day each. This would probably have corresponded to your wish to make Liam an interesting character as well.And there's the problem. If L&P was a competent writer, he could have made Liam's part in the story worthwhile and intriguing. To me it would have added a greater intensity and taboo to what Sophia was doing behind his back. As it stands he's essentially an unimportant npc, to which you pointed out no one even likes. What is the point of him then if no one likes or even cares about the character? He simply serves to increase the length of the release gaps every time L&P decides to render him within a scene and nothing else.
Fortunately, the developer realized that this was far beyond his capabilities as a single person and dropped this plan.