Deus Ex -- You play as a cybernetic anti-terrorist operative in a prosaic and cynical vision of the future fueled entirely by the conspiracies of the mid-90s BBS scene. The world is complex, coherent, and fleshed out. You have the illusion that your choices matter.
Deus Ex: Human Revolution -- You play as a super bad-ass private security in a neo-Renaissance world populated fueled by the hyperbole surrounding transhumanism. The developers deliberately make it less complex compared to the original for the sake of streamlining, use banal pop culture for their "inspirations," and intentionally design the game so that player choices are irrelevant. [0] It can be boiled down to "We want to make a western Metal Gear Solid."
I'll just grab a quote from a random Fallout 3 retrospective here -- "[...] Fallout 1 and 2 were defined by complex storylines, detailed characters and far-reaching consequences to the player's actions. And that these elements are less prominent in FO3, while faster action and stunning visuals have been brought to the forefront." [1]
Or a Thief (2014) review: "The three major strengths of past Thief titles - wide open mission design, sound propagation and narrative - are this game’s biggest weaknesses. That is a fundamental problem it cannot hope to overcome." [3]
Video games "matured" in the sense that they became more like movies interspersed with interactive segments, but the notion that that made them more artistic is pretty unfounded.
---
[0] http://www.gdcvault.com/play/1015489/Reimagining-a-Classic-T...
[1] https://www.rpgwatch.com/articles/fallout-3-retrospective-21...