finding his 'soul', specifically.
During his Gamescom presentation Josh mentioned a common complaint of players who were disappointed with PoE because they found its 'soul' to be missing. Josh also comments that 'soul is elusive'. Implying, of course, that players don't actually have a clue of what it is they're missing. So let's help him.
For people to be disappointed, there must have been certain expectations. We can assume that these expectations had something to do with the Infinity Engine games. All of these were D&D games, and most were set in the Forgotten Realms. I believe this is already the heart of the matter. As Josh mentioned elsewhere, D&D has always been an uneven rules system, torn between simulationism and gamism. And the Forgotten Realms are a notorious setting; they have been called silly, which they often are, but most of all they strive to be fantastical. Or, as I put it, wacky™.
In high fantasy, wacky things always happen. One of the tenets of fantasy is simply to boggle the mind, or at least surprise the recipient. Beings and items show unexpected behaviour or unnatural properties all the time.
In his quest to balance the rules and avoid degenerate player behaviour - which is often just making use of these special properties - pretty much everything in the game was streamlined. If you compare e.g. Baldur's Gate 2 with PoE, BG's wackiness is apparent. Its quirky spells, for example, have far more to offer than PoE's samey buff/ debuff/ damage spells. No hard counters means less impressive abilities on enemies. And magical items hardly ever did anything exciting - not even mentioning the fact that you always knew what they did right away.
The second blow to the traditional fantasy elements that could have been came from the game's tone; it's clearly trying to be serious. I say trying, because serious fantasy is boring and a dichotomy. My argument here rests on two assumptions:
1) fantasy is always escapist
2) escapism is not serious business.
Now, PoE clearly wanted to be darker in tone than the IE games, but dark =/= serious. In many cases, there's nothing sillier than a grimdark setting. So I'd say this in itself wasn't problematic - PoE could have been a dark, but still fantastical game, like its predecessors. What's really problematic is that it takes itself too seriously - and serious and wacky are on opposite sides of the spectrum. As such, this approach was unsuited to a successor of the IE games, or even fantasy RPG's at large. Sentient items, level draining, or raising the dead are more than just mechanics. They reinforce suspension of disbelief by being tied to the numbers. And I don't care if these are old, tired examples - Obs' job would it have been to make it better, not to simply avoid all this stuff.