I've had a look and it's pretty good, I always wondered what a merger of Flashback and The Undiscovered Country would look like - the scenes work well together and ignoring Janeway isn't that hard.

My only gripe is that you've had to include so much other ST VI footage, essentially showing a truncated version of the film, but what else could you do?

Well, if you're really into the idea of doing a one off Excelsior episode try having a look for some more footage of Excelsior class ships - plenty appear in TNG, and in DS9 you might even find some nice battle scenes?

Maybe with shrewd editing you could create an alternative plot that doesn't revolve around the plot of ST VI; perhaps the shockwave comes from something else? And the 'rescuing of old friends' needn't be Kirk & McCoy.

The other option is to go for an extended cut of ST VI using the Flashback footage.

Given the wealth of material availiable accross the films and series, I reckon you could cobble together an interesting piece.