My two cents on the changes.
I have played almost every cRPG there is (from BG, PS:T, through games like Avernum, to Witcher, Numenera, PoE 1 and now 2). I have over 200 hours in PoE 1 and consider it one of the best new RPGs.
That said, as some of the other posters have mentioned, PoE 1 items were rather bland and looked all like the same thing. In PoE 2 one of the great things that has changed was, that items were finally different and did some sort of a really interesting and probable effect that had impact on the game. Also, the game introduced the multiclass system which made for