I'd agree that the DLC somewhat saves the third game. Each adds something to the overall story - Leviathan adds key contextual stuff, Omega adds some decent action set pieces, and Citadel is the emotional end to the franchise.
Even now I can only tolerate the destroy ending. Picking control just makes me feel that I've been wrong all along, and that TIM has been right. Synthesis, speaks for itself, creepy magic gobbledygook.