I have no issue with Thralls needing to be fed along with pets but I see this as an opportunity for the devs to expand on Thralls.
Hunters: Thralls already attack and kill every little thing that comes after them. Why not have them harvest the things they kill?
Gatherers: All those thralls you have sitting waitijng for something to do could be put to work gathering resources or we could get Foragers, Woodsmen, etc.
Farm Plots/Thralls: New placeable block that is tilled ground. You could even tier it for greater yield. This would be popular for folks who like to build communities.