Our recent advance in three-stage nuclear weapons allows us to design more powerful anti-ship missiles.
In fact, if we are willing to make a few concessions we can DRAMATICALLY increase the blast effect of the weapons.
Normal (ie: non-Laser-warhead) missiles will bite a wedge-shaped chunk out of the target ship's armor. It penetrates one layer of armor for each perfect square in the warhead strength... so a strength-1, 2 or 3 missile penetrates one layer of armor, a strength 4, 5, 6, 7 or 8 missile penetrates two layers of armor, a strength-9 to strength-15 missile penetrates three layers of armor, and so on.
Our current generation of anti-ship missiles (the Rapier) carry a strength-4 warhead (so they can penetrate two armor layers), travel at 38,000 kps to a maximum range of 100 million km, and have a 50% chance of hitting a 10,000 kps target (that's a FAST target). Better odds against slower targets, of course. Our current missile also has retargeting capability (so if its assigned target is destroyed before it arrives, it will instead attack another enemy ship in the same group), +32% active homing, and level 2 ECCM (to counter enemy ECM).
With the recent advance in nukes, we can't QUITE squeeze a strength-9 warhead into the Rapier... but we can get really close.
By dropping the retargeting capability (but retaining the ECCM and active homing) we can do this:
Slightly faster than our current weapon, slightly better to-hit (+3%)... and Strength-9 instead of Strength-4. It loses our retargeting capability, though.
The other choice is to KEEP the retargeting capability (and the ECCM, and the active homing) and shave off the economies elsewhere.
If we use a less powerful engine, we can greatly improve the missile's fuel economy (at the cost of slower speed, of course) so we can afford to carry less fuel... and that will allow us to retain the current generation of missiles' retargeting capability and still use the new Strength-9 warhead.
So this version would be slightly slower than our current missile (-3%), slightly worse to-hit (-1%)... but would improve the BANG from Strength-4 to Strength-9 and would still keep all of the current generation's bells and whistles (retargeting capability, ECCM and active homing).
Any preferences between the two? Research both, maybe? Practicals are cheap in research points.