Speaking of Josh, specifically, it is clear that he is a clever man. Pretty well read and would no doubt make for a good chat about matters historical, sociological and philosophical.
The thing is, though, the games he makes shouldn't be vehicles for 'look how clever I am and how much I know' moments. To belabor the earlier point: Irenicus was a relatively simple villain at first glance. His motivation was hinted at during the prologue, and was then spelled out later. Let's sum him up in a sentence:
Vengeful, broken, angry man does mad things for power
The BG2 storyline has you follow in his wake and pick up the pieces he leaves behind, with your paths intersecting both directly (Prologue, Yoshimo/the Asylum) and indirectly (Bodhi, the Dark Elves) before the final confrontation. Each of those intersections gives you a bit more about who this villain is and what he wants.
Now try Thaos... I got through three quarters of POE1, without knowing anything about him beyond 'he can possess bodies' and 'he's old'. That's bullshit. Seriously, though, that's bullshit.
Then we get POE2, and you're conversing with the 'villain' from almost the get-go. Grand. Unfortunately, said villain is also essentially removed from the actual story until its very ending, at which point he is - of course - a plot device. Where's the satisfaction? There's nothing personal (or even really philosophical) in this. Just lame. POE1/2 take care to notice all the trees, and miss the forest entire.