I always wondered about that. I keep wanting to ask people with MMO experience how true that line about DAI is, but there are so damn few of them here.
I've dabbled in a fair amount of F2P MMOs and I think it's a fair comparison as far as the world/quest structure goes. In particular it reminds me of GW2, but it's quite similar to SW:tOR and Neverwinter and many of the others I've dabbled with.
Large areas full of rather shallow quests. As distinct from, say, Skyrim's open world with lots and lots of dungeons. Though, honestly, it's doing a bit of disservice to MMOs. SW:tOR's sidequests are a fair bit better. GW2's sidequests can be more diverse, and they can make use of the MMO nature of the game to make things less static.
It's also got some MMO derived mechanics and conventions, though most of them were in the series from the start like cooldowns and threat mechanics. Getting rid of healers is arguably pretty un-MMOlike. The item system is pretty similar to MMOs, but it's also similar to a ton of non-MMOs.