So, having recently once again dispensed my standard advice of "If you can afford the OP cost of a Tachyon Lance, use that over the HIL every time", and got to thinking - what would make the HIL more competitive?
So there are two things that I think would help the HIL out, comparatively, without making dramatic changes:
1: Reduce its flux cost. Something like, say, 400 flux/s rather than the current 500? Even just 450-ish would be nice, make it so the TL isn't the lower-flux-cost option of the two.
2: Increase its turn rate, or perhaps make it so that it doesn't slow down turning while firing? This might be too oppressive against frigates, though; not sure. Would require testing.
Ideally, I'd like to see both of these changes happen... but I'll admit that that much increased turn rate might be a step too far. Still, the flux cost reduction would be a good start, and would certainly make an HIL Sunder an actually tempting option compared to a TL Sunder.
(Alternatively, if we want to keep the HIL the same, perhaps a small increase in the flux cost of the Tachyon Lance & Rift Cascade Emitter? I'd rather not, though, I like how those weapons work right now...)