The problem with doing that; is it seriously cuts into the Defensive-theme of the faction. Unless it has something odd like double-rate of fire in Cover.
What would be better, is a mobile howitzer that ties into the Royal Artillery abilities since Royal Artillery is the worst doctrine in game. No replacing units or Emplacements.
allow trenches to accommodate them (if they don't already) allow trench to provide rof bonus and slightly higher than normal range (10%?)
trenches are much squishier than current form