I recently started a Campaign as the Prussians on VH/VH and I am only at 1705. I am at war with Poland and Austria, I took that one piece of territory in between my two starting regions from Poland, I crushed Saxony and now I am tearing through Austria. Not once has a large foreign army tried to invade me and I have been largely uncontested. Austria in particular is fighting other wars, and Sweden is finishing off Denmark, but I do no see any imminent threat.
Also in the one pitched battle that I have fought against Saxony they charged me for melee with their militia whereas I was expecting them to sit and shoot for a bit.
I have heard that on VH the CAI is very aggressive, I am wondering are these typical campaign starts? Am I just getting lucky? Or is it just because I am very early into the campaign and my day of reckoning is coming?