While the similarity between Jeremiah's quest for Valhalla Sector (if you go to Valhalla Sector, then we're not sure you're gonna come back) and Sheridan's obsession with Z'ha'dum (if you go to Z'ha'dum you will die) is striking, and there's the overtone of "If we all don't band together, the big nasty enemy is going to overcome us all," those motifs - the journey motif and the underdog motif - are tried and true ways to tell a story.
Jeremiah is pretty different, except for JMS' copious use of those motifs. The only time I really see "The Guy Who Wrote Babylon 5" in his scripts is whenever Markus yammers on and on about alliances (I really hate that, for some reason) or when there's trademark JMS exposition ("let's walk down the hall and I'll tell you everything about the Burners.") Gaaaah. Shades of Martel's "let's stand by the Liandra and I'll tell you all about my childhood."
Tripwire and Firewall were unlike anything he did on B5, I think. That was some cool television.
All told, my third (or second!) favorite episode of the season, "A Means To An End," wasn't even written by JMS, but by Sara Barnes.
And I agree. "Out of the Ashes" looked like an afterschool special... I didn't enjoy it all, and when the townspeople showed up brandishing weapons, I groaned out loud. I also kept on thinking Red and Maggie had an ulterior agenda, but then, I'm paranoid...