Version: 0.82.6.1-20-g872d999
1.Advantages:
+1.a. Units with high maxVelocity and low turnRate path well.
+1.b Units drive slower in bumpy terrain as if they slow down because it is rough terrain.
2. Disadvantages
-2.a. Units with high maxVelocity and low turnRate deaccelerate to turn regardless of turnInPlace=0.
-2.b. Units will drive slowly in slopes regardless if they are going down or up and regardless if the slope is bumpy or not. Spring 1944 vehicles suffer from this(a combination of high brakeRate, high maxVelocity and low turnRate).
Explainations:
2.a. simply makes turnInPlace=0 useless on alot of units.
1.b and 2.b means that balance and gameplay suddenly changes alot. While 1.b might be nice to have 2.b is not my in opinion.
1.a. Units can still get stuck but it can almost be considered rare.