To put it succinctly, right now we can choose between "Stable" and "DevBranch". Wouldn't it be possible to simply add a branch for several releases e.g. "1.20", "1.22", etc.?

The problem lies in automatic updates being pushed through that break one or more mods and potentially de-stabilize an ArmA unit's ability to play missions until the issues are trouble-shot and fixed(could take hours or weeks). If we were able to control our game version and stop updates(the steam option of "do not update this game" does not work), as well as roll back 1-2 versions to give these mods times to update as in ArmA 2, it would greatly enhance the stability of units that rely heavily on mod-packs(most ArmA units).