Why do you think Caitiff had to be LET IN into Falconreach?
Guardian Kain had to open the door (gates, in this case) for it.
...Caitiff's blast made a crater in the earth. It MELTED Ash's blade. I suppose the gates are enchanted, but come on.
And if normal axes can be used to break down a door (they can, although it'll take quite a while), than for an enchanted axe wielded by a super-strong person (at 200 str I suppose the hero is about Thor/Hulk strong, or at least Cap. America) it should be a piece of cake.
Not to mention some powerful spells some classes have.
Oh, and a Riftwalker should consider this whole discussion hilarious (unless you have to see a portal's location in order to create it).
So it makes sense for doors in places like the Valtrith tomb or in Blackwyn, where there are special defenses, or in inns where we don't want to cause damage, but in many places it's ridiculous.