I notice the AI tends to swing the lances around when fired. I have a 4 Lance Paragon for fire support and when I see the lance fire, it tends to waver a bit instead of just being in a straight line. Also, friendlies may stop firing when an ally travels into their line of fire, but that doesn't affect the ally from recklessly flying through the fire in the first place, I've notice.
There's been countless times when I'm firing off with my personal Paragon (4 Auto-Pulses) and a one or more of my Tempest decide to cut across THROUGH my firing line while strafing the ship we're both attacking. Since it's focused on attacking and avoiding ENEMY fire, I'll wind up cutting off its rear side if I don't stop firing in time. So I think part of the problem there is the fact your own ship don't try to avoid fire FROM friendly when manuveuring. I think the extreme range and burst-y nature of the Tachyons compounds the problem. You can easily have a clear line of fire, shoot, and while the shot is traveling/alive, a friendly decides to cut across the firing line of the Lance(s). I've seen that as well. THe firendly fire avoidance in the ship AI works well enought with just AI ships (Cease fire when Friendly approaches), but it doesn't quite work as well when it's the Player-controlled fire and an AI ship approaching (or significantly delayed/slow shots from another AI vessel).
As for the TL vs HIL discussion: I find the HIL can be used for keeping constant pressure on fighters. I have an Oddy with 3 HIL's and it used to keep fighters at bay quite well. (I've stopped using it once I got my second Paragon, though I'm currently using a 8-frigate fast attack fleet.) TL's have a long reload/refire time. If you miss, you just lost a lot of potential damage. Granted, if it does hit, it HURTS, but still. Misses with the TL's (if somewhat rare) can cost you quite a bit of time waiting for the next shot. While the HIL's are practically useless against larger vessels, I find it useful for constant pressuring of the smaller enemy forces like frigates and fighter wings at long range.
That said, I still love having my Quad TL Paragon snipe suckers from the other side of the map ^_~ It's so fulfilling when you see an enemy frigate pop out of the FoW into the LoS of a one of your own frigates on the far side of the map during opening capture runs and 2 seconds later, it's dead from a TL slavo while your own friagte is on its merry way to the capture point the enemy frigate was heading for ^_^