I agree that Solace projectile needs more acceleration as a first step. Other measures may be required later.
As an aside, the comparisons to t3 bombers are apt but there is a key difference: T2 land/air cannot effectively shoot down a t3 bomber (no sam/asf) but T2 navy cruisers all have effective sams. As such, even a rushed Solace is nowhere as good against ships as a rushed t3 bomber is against land. So ideally, the Solace will need more hp/dps/etc than a t3 bomber to have the same superiority over tech 2.
Here are some other ideas to consider for buffs:
- Split target projectile (auto disperses to kill multiple subs)
- Powerful anti missile defense (like the t3 bomber but netter)
- Brief speed boost when it drops depth charges (to help escape the inevitable return fire)
- Teleportation after drop (teleports forward, again to help avoid enemy fire)
etc