Removing brace without doing anything is going to leave the british forces with no non-doctrinal bombardment options, apart from the 25 Pounders who can't kill anything and are slow to react. They would at the minimum need a HP and defence boost.
What I'd prefer is to make the Pit itself a defence with no inbuilt weapon, but the ability to deploy any on-the-field Support Weapon in it. The Pit can't be decrewed and takes damage before the support weapon does. Finally, add a Mortar. THEN Brace can be removed.
+1 me thoughts exactly...thats how the British MG emplacement in the game works and its great