This movie was more of a dramedy and I don't think that works for a show like B5. John Sheridan and many of the others are oddly quirky stumbling into broom closets, complaining about socks, etc. Many of the characters in B5 were fully adult military and political experts with wars and accomplishments behind them. They were not without humor but they had maturity. Not every character has to be spiderman nowadays.
Also the love message at the end was pretty corny and their choice of character animation was stilted at best. The only two real good things I have to say are that the space battles were beautiful and Peter Jurasik's presence as the voice of Londo was a gem as always.