One of my favorite builds in Kingmaker was an Aldori Defender/swordlord/thug/duelist/monk mix wielding a dueling sword that would just run into battles to gain aggro and generally leave untouched (in normal ofc, Dex tanks were useless in harder difficulties)

Is that kind of tank still viable in WoR?

My current run has a magus (sword saint)/duelist mc (18 dex 18 int 13 cha, the rest 10 keen kitsune), and early on they've always been 5-8 AC ahead of Seelah. For instance, at level 2 in the first dungeon, I hit 28 AC with buffs, where Seelah was at 22 (and was taking way too many hits). At 15, I have 55 ac (and there's a mythic ability that would give more ac that I haven't taken yet), while other characters are mid-upper 40s.

Fort and will saves are weak, but the only things that really touch them are 'extra' bosses (who are absolutely ridiculous and have total attack bonuses around the same as this character's AC, even on normal).

Note, some stuff regarding AC has changed from Kingmaker - first, bracers of armor are base armor, not enhancement (so a +1 bracer is the same as +0 padded armor, minus the dex limit), Second, stuff like sword saint's and duelist's canny defense (int bonus added to AC) are one point per class level now, so those come more slowly.