My only suggestion at this point would be to cut back on the Hull Plating and dump those points into Structural Integrity, although at this point it's probably more personal preference since I'm pretty sure the percentages for the resistances and the HP boost are similar. And you may want to put a few points in Power Insulators, but that's again a personal preference.
It looks like this is going to be one tough nut to crack in battle.
One more thing though - I would definitely not bother with plasma weapons. The proc just doesn't do enough damage, even though it applies it directly to the hull. Generally plasma weapons are considered the "junk" weapons in most game chat convos. They're good, IMO, for getting cheap, high-Mk weapons when you're first getting to Captain or the Admiral ranks, and they seem to do a bit better at lower ranks so they may be worthwhile there, but beyond that there are far better choices for armaments.
I've reduced a few of the expensive 9 point skills and bumped up the cheaper shield skills and got repairs.
I've also decided to ditch Tractor Beam entirely so that I can get both Polarize Hull *and* Science Team - I hate being stuck in a Tractor Beam and that instant shield boost comes in very handy sometimes.
I do have the Accuracy trait, and I chose Antiprotons because the 20% crit severity seemed like it would *always* be useful. The other sensible-looking options were Plasma & Disruptor. There seems to be some confusion over whether the Disruptor debuff stacks and AP looks cooler than Plasma...
I wouldn't say I'm trying to min/max, it's just that respeccing is expensive so I want to get it right! I'm very grateful for all your comments, feels like I've learned a lot from this.
Another update after a couple of weeks of testing and refinement.
I was finding in STFs that while I was almost impossible to kill my DPS was very low, and that threat control in this game seems to be as much about damage as anything else. With that in mind, plus the realisation after playing my Tac character a lot that I was never going to out-DPS a good escort, I respecced to a more DPS focussed build that forgoes threat control and a small amount of defence: