I do think that the damage incurred by missiles is a good deterrent. Many players work hard to achieve their infra goals and that 3- 10 mil can be a lot to many of them, especially if multiplied. And for those at lower city levels, it can be especially frustrating. Eradicating the ID in its current form would put the advantage toward the larger and more powerful alliances who have many members in the lower city counts. As was noted by Tyrion's response, they would love to see it nerfed in any way possible. That would mean less damage for them and less chance of a outnumbered combatant being successful in imposing any real damage toward a larger aggressor. The result of that could very well be more bully-boy tactics by the larger alliances. The larger alliances have the manpower necessary to impose their agendas already, why make it more easy for them and harder to defend against? IMO, the ID offers a good defense for both sides. If one is worried about taking damage from missiles, then they should get it. If they would rather have a different project in that slot, that is their choice. As has also been noted, the damage isn't massive, just a deterrent. And that is a good thing.