For the target-priority turret thing, would it also be set up so that the turret auto-selector sets these to maximum preference? For example, if you target a Sath, even from behind, it selects one of the forward BFReds first. Even as you cycle through, it tends to prefer these. Perhaps the sexp could be fitted with a 1-5 number, indicating turret priority.
Regarding mines, I proposed a minefield system in the Collaboration Forums, which would use something like the asteroid code as a basis, in that the FREDer doesn't have to place all the mines they want on the grid, taking out of the 100 ships-placed-ships-on-the-grid limit. It would use either a new section in the asteroids table, or ships table, or perhaps an entirely new minefield table file, allowing many properties to be applied to mine types, such as yield, stealth, defenses (turrets), proximity detonations, target class preferences, swarming, etc. The minefield mission editor would also allow the FREDer to specify the size and density of the field (just like with asteroids), as well as any drift or motion of the mines, and also arrangement. For example, you may want an apparent randomly dispersed mine layout, or perhaps an ordered system, like grid, tetrahedral, etc. Having the mines themselves as part of the ships table file however, would allow the mission designer to place plot-strategic mines, rather than relying on the asteroid-based code to do what he/she wants. Thats not to say that anyone agreed to my proposal, just that I put it up... with perhaps a few more minor refinements here.