You're vastly overstating the difficulty of DAO. The combat can be played almost entirely on autopilot. On my current play through, I an my companions are all level 8 and 9, and the only recruitment quest I've done so far is Broken Circle (and even then I skipped a good 80% of the actual quest by skipping the Fade sequence, so I missed out on a lot of XP). Literally all I have to do is position my dual-wielding Warrior Warden behind enemies to attack and wait for Alistair, Morrigan, and Leliana to finish killing everything. The only times I bother paying attention to the combat is when there's an area with a lot of environmental damage (whether through traps, mage runes, or ballistae), because the AI can't navigate worth a damn.
The combat is easy in DA2 and DAI as well, but at least there you actually have to be playing since it can't be all nearly automated.
By saying I was able to beat the game on nightmare just by unleashing my party on autoattack (only Wynne's single target heals, buffs and party sustainables were set in tactics menu, they didn't need anything else) is overstating its difficulty? Ok then
I was just wondering if the game is that easy for everyone or if the game is only super easy for players who know what they are doing. Because every game out there is easy for people who know what to do. Would for example Hearts of Iron be an easy game for an average Joe? No, he wouldn't have a clue what the hell to do. Is it an easy game for a person with substantial experience with grand strategies? Yes, it is, especially when playing with a super strong country.
Ok, DW warrior, the single most OP class in the game, but you must have an idea how to build him in order for him to dominate since the early game. There are also the DLC weapons and promo items, for example The Edge dagger is super powerful very early (you can equip it in Ostagar a tier 6 weapon instead of tier 1 or 2 you would normally found). Keep in mind they were not avaiable on launch and in the case of promo items not for everybody back then. If you are using them, the game is even more easier. If not, then point withdrawn.
One tip, you don't even have to position your DW killing machine behind the enemies, you are not some meager rogue. Just taunt all the things with Alistair and charge with your Warden head-on. The flanking bonuses for non-rogues are not that great anyway and you'll save time by not running around the enemies, since they will be dead in few hits anyway. Again, does this show us the game is easy? Not by itself.
If you used the mod "Skip the Fade" you didn't miss any XP, any stat points and any codex entries, it is a well thought out mod 
I don't want to say DAO was overly difficult since if you actually read my posts you can see that at least for me it was not. I am only trying to say the game required more thought and experience to be easy than DAI. In DAI you are not required to think much, you only need your barrier, holding down your LMB / R key and in the early-mid game button mash every cooldown available. And ofc DAI has its share of ridiculously OP and completely broken characters as well, but in this case they are OP so much no other class in previous DA games can match them. In the case of Knight Enchanter, you can solo the game from a certain point just by facerolling on your keyboard and in the case of Tempest, you can kill even the highest lvl High Dragon on nightmare with a single ability in the matter of less than 5 seconds. The OP chars alone don't show us how the game is easy, but they deserved to be mentioned.