As I understand it, Hoon and the General Staff are after more uniformity. They want to be easily able to transfer troops from any given unit to any other unit without complication. For most units that isn't a problem, but it won't work with assault units or the more elite. Even the US Army knows better than that. Units with real battle traditions and unit pride shouldn't be messed with. It only destroys morale and reduces the effectiveness of the units in question and combat effectiveness should never be sacrificed for command convenience if you want true military professionalism. I would consider the Highland regiments to be assault and elite units given their long battle histories and overall effectiveness in combat.