I can see some benefit to an IC in WE, but I think that it is a sub-optimal purchase. Lets look at the main reasons for the purchase:
1. Build naval units directly in sz 6, 7, and 13.
2. Build infantry and possibly fighters directly on WE.
First and foremost, in most games Germany’s primary target should be Russia- which means spending most of your money on troops for the eastern front. Spending 43 IPCs (IC + AC + Des) on units that do not help with this makes putting any kind of early sustainable pressure on Russia near impossible.
Second, fighters are more flexible. A destroyer and a fighter have the same attack, but the fighter is cheaper by 2 IPCs. Fighters can significantly bolster a territory’s defenses, provided you have infantry as a shield. They can not be attacked by naval units (excluding bombards, which should kill infantry anyway), and defending subs cannot hit them at all. Neither can an enemy’s air force directly attack yours- they have to attack the territory they are stationed in. If needed your fighters can be sent east to help with attacks against Russia, then pulled back to help defend in later rounds. No naval units have the same flexibility. In addition, the allies can afford to spend more on their navy than you can on yours, especially the US.
Third, why not just build infantry in Ger and SE? They only take 1 turn to get to WE, and this saves you 15 IPCs. In my opinion, the only reason for Germany to build an IC anywhere is if their production is maxed (16 inf alone is 48 IPCs- most likely you will make some art/tanks instead of all inf).
I confess that I sometimes purchase an AC on Ger 1 in sz 5 and land a fighter on it. This is to keep the fleet alive long enough to regroup with the BB+Tns in the Med. But that is the extent of my naval purchases in almost every case.
There’s my 2 cents. Spend it well