I was wondering the same, the purpose of the poll, or what of it once it's closed?.
I don't know, Perhaps he should cull some characters, he has already set storylines to end by choices and maybe other storylines will face the same situation in the future so, perhaps he could or should cull some characters as well based on the poll? or maybe simply just reduce their content a bit more (look at Liam's count and though I'm not a Patreon to know the current situation) he was low on the list so maybe L&P could reduce some content with Liam or reduce the Good Wife route since Liam doesn't appear to be a very favorite among the voters.
Is Liam essential to the game overall?
yeah, maybe. To keep Sophia anchored to someone while she does things with the rest.
But is Liam that much necessary since he is not favorite among the voters?
Apparently not that much.
Then again, yeah he could just be killing time haha.