Idea of a heavy missle with a giant range (up to 1.5 km!!!) its needs a special pointer (with 150 meters range) that will aim missle at the target or can be lunched manually without targeting, after start target will get a just target-like symbol (enemy see it too and will get an alert even if shot was manual) as missle will start to fly straight to target with turning at any side after aiming. Its cant be destroyed and have a giant speed (about 1.5 times higher than nukes). Have penetration (because of high speed it should have some penetration) and giant AOE damage (about 40 meters and 1M dmg(5 times bigger than a normal nuke)) (splash work like nuke instead of working like prism). As ammo it will use: 1 enriched uranium and 20 nuke parts (so people wont shoot manualy without being sure that they will hit enemy and will balance weapon more). For balancing it could have a very big launcher (maybe 4x6 or 4x8) that can shoot only straight forward unless you target it with pointer so it aiming will work closely to nuke aiming + give it long reload (20-30 second will be enough I think)
Its will make kaiters less OP and make counter to them, make possible to attack from a big range without using NRE (Nuke Range Extender), will make very slow ships an easy target and will make fleets more usefull (as example you can make 3-5 ships with 1 launcher of those heavy missle per ship and 1 little ship with pointer and shoot enemy wwwith 3-5 missles at the same time)