The decoration buffs were changed to have a countdown timer and now there are also decorations that give negative moodlets. I believe this decision was the result of a combination of the Eco Pack overhaul and many simmers who complained that Sims were constantly happy and wanted the decorations buffs changed.
Personally, I think it's much better now; balanced, and more manageable for those who want Sims to show emotions besides "Happy" all the time. The decorations were way overpowered before.