Small Note: If this missiles do a lot of damage (relative), and are fired by a missile specialist. It's VERY easy to take out one of your own allies.
45% passive bonus to damage, and X5 from Deadly Missiles... The ever so humble 20 damage projectile becomes a hefty 145 damage spray of doom! And considering how many missiles there are in 1 pod you can fire A LOT of them in the duration of Deadly Missiles. Also adds a fairly large boost to AnitJamming. (With 5 uses of DM per system, its pretty easy to keep up)
I'd give cheaper ones with more warheads to System Specs. Just to distract enemy ECM/AMS. Unless of course you don't have a Missile Spec, but I love Missile Spec. The ammount of damage you can do with 1 Warhawk is amazing, take out entire groups in 1 missile.
Even short range MIRV like this, with 4 med damage warheads would be cool. Ones made more for killing few weaker targets, or doing big damage to one hard target in the middle of a dog fight. But games in space need to be somewhat over the top.
For my game I reduced the costs for all missiles ~25% 
just to make buying so many less of a pain. Considering doubling the pod size (& .: availability, as shops stock in pods). Though I found a way to get unlimited money using 1 ALRM and 1 Cheap Ship. 
Edit: Considering following valky's little guide to add in a T-5 Smilodon, I prefer that style of ship to the Hrimthurs-T. Even with just armour bonuses its a better ship! If it goes ahead, I'll have it done this weekend. Add a system slot or two for a radar & something.