Ion Cannon is pretty good. =D Has lots of good benefits even though it does reduce damage. Also note, on a 3 attack ship, using the Ion cannon at R3 is typically better than your primary, as they don't get the range bonus on defense. Statistically, you're not likely to do more than 1 damage at Range 3 (statistically).

I feel like HLC is more potent though.

On Tie Defenders, i really like them. again, They make your R3 shot great.

But... with 3 tie defenders.. would you rather have 3 ion cannons, or 3 hull upgrades? In a way, it seems like 3 hull upgrades just really do what you want the defenders to do. Last a long time.