How do you think those conquered 'Norse' provinces become 'English'?
Trust me, it's not by mutual understanding and cultural exchange.
But I agree that the ability to 'counter-raid' would be cool.
Maybe even give a character modifier that discourages Vikings from raiding you.
Absolutely aye on the first point, 'tis a good one. A lot of things are "behind the scenes" in CK2, and the true beauty of it is that when it works, and it mostly does in spite of how much people, myself most definitely included, rant and rave about it, it works absolutely beautifully when it comes to modeling the correct outcome. There's a reason why people like you and I just can't let go of it
I guess what I really wanted to say was what you said in your second point: I really want to be able to punish the everloving crap out of somebody for stepping on my toes. I want to be able to mount a punitive expedition and roflstomp the snot out of the bastards while humming "The Rains of Castamere". For a price, of course. It shouldn't be cheap or easy, but it definitely should be doable. And it should, as you suggested, make your enemies fear you if you go all out and invest in it.
But we can't. The only thing we can do about raiders specifically is to adopt a defensive posture and just accept it for the way life is. Build up your castles, create strong dukes to take care of Coastal Defense and then hope that it all goes away eventually. Which is all OK. Being defensive is and should be an
option, but it shouldn't be the only one. Going into a holy rage and investing every ducat of your income, even taking out potentially ruinous loans making the bastards who stepped on your toes piss themselves at the merest thought of ever displeasing you again should be
another option.
I realize that we can't have everything, but that truly would be nice. I mean, the raiders can burn down your holdings and set them back years and years while you're building them back up, which is all OK and very historical, I don't want a bit changed about that, but why can't you do the same to them????