ORIGINAL: Garth Vader
I thought pioneers were used when assaulting a city or heavy forts. Why put them on motorized divs?
Depends on the situation -- in the early turns, one way to maximise the longrange strike power of the armoured forces is to beef up a mot. div. with a stug or flamm panzer, a flak battalion or panzerjager, and a pioneer, and then you have a multipurpose mobile infantry division which can be used to take out small blocking units safely with hasty attack. Sometimes, you will encounter a low CV unit which needs to be moved to free a path for panzers well into the enemy rear and the mot.div, supported, can do it reliably.
Of course, you are right in most other situations - pioneers should be used with infantry for big assaults. Remember, too, pioneers help in crossing rivers (AFAIK).
I still remember cardboard!