I've explained my disatisfaction with Into The Fire in the past. I'll try not to go into great detail again. To be brief:
(1) The fact that a couple of ships with people we've never seen on them sacrifice themselves for Sheridan doesn't seem like a show-stopping moment to me. I certainly don't believe that the Shadows (or the Vorlons) that we've seen thus far would blink at this. They'd certainly have mowed down a great number more ships before even blinking.
(2) Sheridan doesn't have a lot of moral authority, IMO. Every time I see the beginning of season four, I find myself agreeing with Garibaldi. Who the f*ck is this Lorien guy supposed to be? Sheridan doesn't stop for a second to explain himself to anyone. He certainly owes this to his command staff. It's a good thing they back him up regardless.
(3) There's the inevitable anti-climax of the only way where the human (and aliens) are able to defeat the Shadows and the Vorlons is to get a few other First Ones.
(4) Add to that the lack of complexity in characterization for the Shadows and the Vorlons in the final scene (Sheridan's paternalistic "now get the hell out of our galaxy" is the obvious, and embarrassing, example that continues to be glaring).
I love the idea that this is an ideological conflict that cannot be ended with weapons. But I absolutely loathe the execution. Others, of course, will disagree. But there it is.