I might be on my own here - but I'm not crazy about the direction Nick's character has taken post break up.
He's at his peak in season 2/3 - a loveable idiot who's lost in life. In season 4, so far, he's just completely idiotic and pathetic.
They did make Nick kind of fool. Much like in Parks & Rec. Andy went dumber and dumber every season, in an even heavier degree. But I guess because Johnson is just a really good actor (imo) they still pull it off quite alright. That scene with him and the captain in a room made him look like a big goofball but he played it out very well. They really like to use the fact that Nick can't keep secrets anyways, something that keeps returning over the years.
Oh and I'd like to see something involving Tran again. Nick and Tran are perfect together. Just like that homless guy who came from the future or something