Hello Luc
So I take it that we would use a standard Saladin FDD rather than the L.S. Destroyer for the FDD
It depends on the year (and thus the ship's refit). The way I see it, and it could just be me I know, the Y175 refit was a good time to say "hey let's do the TMP era refits now, and have Enterprise refits for everyone!" so that the game could actually show some progression through the technologies.
ie, old image from my OP+ pages..
Additionally, the Saladin-class DD gets another interesting model later on, when it becomes an Advanced Technology Destroyer: 2 engines.
ie:
However, this Fed DDV was a unique ship.. and I don't think it never really progressed beyond TOS era designs .;>