tl:dr: Change Wagner torp DPS from 3 to 9.
Edit: I'm using a revised algorithm now, wagner efficiency is 49, sliver is 152. My recommendation for the wagner remains the same.
Brick raw efficiency is 55, so the torpedo DPS could be doubled and it would be fine.
Seraphim T3 tank is 47, so it's about the same and DPS could be doubled in the same fashion.
The Monkeylord is only 5, so it could be given considerably better torpedoes without too much risk of imbaness.
The megalith is 24, so it's torp dps could also be doubled without too much worry.
Based upon my numbers, recommendations for changes to units other than the wagner would go as follows: Brick torp DPS increase by 1x, Seraphim T3 tank by 2x, Monkeylord by 9x, and megalith by 1x.
Also karo, the torp efficiency of the serpahim destroyer is 218, so it's not going to be cost-effectively beaten by wagners unless the torp DPS is greater than 12. For reference, the Aeon destroyer torp efficiency is 268.