@Tanner Glass is right when it comes to gameplay and progression systems.
in addition to that, diablo 2 also had a very cool setting, highly memorable characters (tyrael and diablo in particular are still widely recognized across the world 20 years later) and a great soundtrack. diablo 2 was also an absolute masterpiece when it comes to atmosphere and how the game world 'felt', which was achieved through a combination of lighting, sprite artwork, animations, level design, sound effects, and music. the game was revolutionary in many ways.
anthem (from what i've seen of it) has none of that, everything looks like a generic destiny/warframe ripoff with not much going on in terms of creativity or innovation.
hell, diablo 2 had more soul and emotion in just a single cutscene than you can find in all of anthem:
https://youtube.com/watch?v=XRXP5td0ZrA