Honestly, I just feel like putting it forward that far too many people put far too much value on AC. I mean, really... in one campaign I'm in at the moment, I play a front-line, dangerously aggressive storm sorceress who consistently puts herself front and centre and in harm's way, and her 10AC (10 dex, no mage armour) hasn't really caused her any problems yet, by level 10 and about two thirds of the way through the campaign. I work on the basic assumption that attacks will hit, and I play accordingly - occasionally something low-rolls badly enough that I can shield it, which is a bonus, but otherwise it's no big deal. AC is really not the be-all end-all that many people make it out to be.
This particular argument sadly doesn't really hold much relevance here. This just means you have a DM that is balancing encounters around your party's limitations, as a DM should.
A video game by default is balanced in a far wider scope, though there absolutely will be some baseline expectations on what a player's stats should be at a particular point in the game. In an environment where the game can't freely add or remove enemies on its own, the baseline will most likely assume that there is going to be at least one or two party members with moderate to high AC.
Though one would hope that Larian has far more reasonable expectations, lest they condition the community to hyper aggressively chase AC like the Pathfinder games.
