The TL was OP back before we had CR, in an age where you could just deploy your entire fleet at no cost. Back then, well, if you had three Odysseys with Tachyon Lances, then you'd deploy all three in every fight.
Now? Okay, you technically still can do that, but it'd be expensive & reduce your ability to fight multiple battles. Plus with active time limits on all ships, there's no forever-kiting. The things that made the Tachyon Lance absurd have other limits now, so it should be safe to bring its damage back up closer to where it used to be.
Of course, then the HIL would need a bit of a buff, too, but it needed that anyway.
As for new weapons... like others here, I'm hoping that one of those is a new large missile system.