If it had been up to me, I wish they had been able to make a feature film instead that brought all five captains together, but keeping to what they had to work with, I'd have rather it been:
-A two hour episode
-Set on the Titan instead of the Enterprise-D (maybe even have spent some of the episode not on the holodeck and getting to see the Titan at work?)
-Not had the threat been an alien of the week, but rather a species with more Star Trek weight (i.e. Klingons or Nausicaans or something)
-Not kill Trip off (or if they really had to, make it be bigger like saving the entire Federation signing audience)
-Shown something from the Romulan war
Past that, I really don't have
More than anything, making the interaction between Riker and NX-01 crew both real and consequential would vastly improved the episode. Even a time travel episode that put Riker (and Troi) in the 22nd century would have been a major improvement.