I'd argue that was down to who he was partnered with and the little to no effort given last season from his D partner.
Lou's season under skalde was an awkward one, he was faster than previous seasons and seemed to be tuning in his one timer which was great in my opinion, but once skalde left and Dupont took over he just suffered like majority of the team did. He was even benched for 7 straight games because of the coach playing favourites which left him frustrated and unhappy, especially when he was needed on the ice more than Reid was, but Lou has moved on and I have a feeling that if the season does turn out to be a hard one for the Devils because they lack an ice marshall on the ice he would come back if asked because he loves the club and respects the owners.