I was always a fan of the scout unit. Even more so after I discovered the flaws in this system when I first started playing. I actually started a new world on TW1 but couldn't deal with the outdated graphics and slower pace. TW2 has many awesome features, but this is a bluster to the name.
Work in the tier system like the old version and have tier 3 be accessed at the highest level, giving catapults use besides demolishing a village that is already empty. Could even add a scout weapon to pally's that change their attack speed to that of scouts if only scouts are present, and empowers them either in attack strength (scouts are on their own plane of battle) somehow. Could even disable a certain targeted bonus (such as recruit speed in barracks, or veterinary in the hospital) for the next attack or period of time.