First of all, it appears from how things are framed and have been framed in the quarterly updates that Blizz is moving towards D2. As an example, Blizz stating they're trying to move player power away from items a bit is huge when you look at D3 and how insane power scaling is based upon certain pieces/sets. They can have a marked effect, but D3 is the extreme where not only does the baseline player power feel anemic, but also most gear is just worthless to where the power curve just shoots up at an insane exponential rate based upon 1-2 pieces. D2 had more power distributed baseline in the classes, as well as the talent trees, all while allowing gear to matter.
As an addendum, PoE is a great example of how even yellow gear can be powerful in the endgame, or even more powerful than uniques in many cases. D3 at the start had placed some value in well/perfectly rolled yellows being great, but current D3 has yellows as trash tier in pretty much every scenario while legendary items are always BiS. The trick is how many stats you have, how they're weighted on the items, if the stats can vary on legendaries, the amount of customization/crafting you can perform, etc.
Secondly, not everyone likes the same thing. Furthermore, not everyone likes new games being the exact same as its predecessors. While many people like the systems of old, many people want new systems instead. Just because something was popular decades ago doesn't mean it'll be popular now, or that it cannot be improved. It's a precarious path to travel, offering new experiences and systems while preserving the integrity and soul of the series, and I don't think people appreciate how bloody hard that is to achieve.