The only change I would make to the Wrath of Khan uniform is to lose the movie-era captain rank pin (the only one available) and replace it with contemporary rank bars, arranged vertically instead of horizontally on the rank pin strip.
Either that or go with a TNG-era pip arrangement in a pattern similar to this:
A=hollow pip. B=solid pip. C=pip cluster surrounded by bars for admiral
I'd rather see them add all of the original ranks...
I forget the reason why they didn't have all the original rank pins available. Was it a copyright issue?
If that is the case, then what I suggest would be a quick fix to the issue and allow the WoK uniform to be fully viable at all ranks. In fact, I'd like to see them add the movie era rank pins, AND do something like What I've suggested here. It would extend the use of the WoK uniform by adding a customization option.