This is not a difficult weapon to mount by any stretch of the imagination. The negligible power cost of 2 means all you need is 60 crew - a large crew quarters lets you mount four MWM for a grand total of 16 power and a module slot.
It has 1200 range, which is the widest anti-shield weapon range outside of the disruptor missile. Range translates into concentration - it’s possible for an entire fleet to focus fire on a single ship, and no shields are capable of resisting it.
It shoots 5 missiles a time. It gets a dummy missile launcher effect for free, with the added advantage of none of the missiles actually being dummies. It is a consistent, powerful weapon that makes all other missiles in your fleet better - point defenses are increasingly overwhelmed the more of these you use.
It is a missile, which means you can use it in conjunction with painters, hard countering any attempts to exploit tracking speed.
Compare it to the closest competition:
MWM: 160 cost, 38 dps, or 7.6 dps per missile, 80 damage volley
Torpedo: 120 cost, 18.9 dps, 55 damage volley
Fast missile launcher, 100 cost, 15.8 dps, 31 damage volley
Heavy plasma launcher, 160 cost, 12.5 dps, 40 damage volley
Even if you try to adjust for cost, the MWM comes out on top. It’s completely impeding on what one would think is the torpedo’s territory - the torpedo is slower, has poorer tracking, is easier to shoot down, and the utility of slightly more armor pen is easily dwarfed by raw firepower. The fast missile launcher’s trait of being faster to slip by point defense is almost a quaint consideration when one can simply shoot an additional 5 missiles instead. The MWM is both the higher damage and higher utility option. Don’t use anything else.
Like all missiles, this weapon shines in scenarios like Paleovost IX (slower movement to hurt both fighters and rushers) or Zoophon (no dreads for easy armor tank).
It’s broke. The long range makes it favored by tank fleets, so many indirect nerfs (like a weight increase) aren’t going to mean much. Buffing point defense will just lead to an arms race where every other missile type is left behind. This weapon, at current damage values and missile count, is a serious problem.