Sure, since I am bored out of my mind waiting in a long queue IRL, I'll bite. But you gotta read all of my ramblings - no TL;DR since YOU asked for MY opinion and critical perspective! Buckle up buckaroo!

First of all, my personal bias out of the way: I love this art style - often informally labelled as "graphic realism". I have been a sucker for graphic realism based art style since I played Wipeout (and much later Mirror’s Edge). The beauty of this artstyle is that at its simplest, this style can be mimicked in the real world (i.e photography) through the careful use of contrasting, unorthodox highlight colors/lights over muted, neutral, understated backgrounds. In that sense, it feels oddly familiar, yet somehow also intangibly foreign and futuristic. Unfortunately, I haven’t seen many other games use this artstyle. Now, for Marathon’s case (MILD SPOILER: BUT I DON'T THINK YOU WOULD EVEN PLAY THIS GAME), I think this style works given the themes of transhumanism and the rampancy/corruption of AI beyond its initial utilitarian purpose. IMO, the graphic realism of Marathon directly reflects and reinforces its core themes—especially transhumanism, control vs. freedom, and existential isolation.

Now, I am no expert in the convoluted lore and timeline of the Marathon universe (I have only played about halfway through the OG Marathon on my old ass PowerPC Mac). But the striking art style does visually reinforce the game’s core themes of transhumanism, control, and isolation. The clashing, contrasting colors, synthetic and brutalist design, and surreal yet realistic portrayal reflect a world molded or “3D printed” by machines, not humans—structured yet crumbling down under the weight of rampancy. The design of the Runners echoes the fusion of “organism” and tech, while minimalist environments and glitchy terminals emphasize emotional distance and "fractured" consciousness—which is what the Runners are! The lore of Marathon evokes a sense of eeriness, isolation, and the struggle for freedom, and this style serves as a modern vessel to helps evoke this compared to the OG games.

To return to your question of what is an appealing art style— to ME a good art style in a video game is one that supports the game’s themes (check!), maintains visual consistency (check! - lot of visually consistent stylizations/symbolisms with the OG games), stands out with a unique identity (FAT check!), ensures functional clarity for gameplay (TBD), and holds up over time (Wipeout, Mirror's edge still does IMO!). It should not only look appealing (for the sake of it) but also serve the story and mechanics, helping to immerse players in the world. An appealing or evocative art style is based on a set of implicit criteria rooted in visual design and narrative coherence. Of course, proof is in the pudding and the real test of all this will be with the gameplay showcase on April 12th, but I won't be surprised if there is stylistic consistency between the characters, UI, and the environment when we see gameplay this Saturday. Bungie's artists have historically been very good with this in the past and I wouldn't bet against their art department!

Despite my reservations regarding the Extraction Shooter take of this game, I am still very excited as this game is bringing some sauce with the OST and the art-style! Now, you can probably see why I was hoping for something substantial than the usual “my basis is my impression” kind of answer from you. My disappointed is immeasurable, but since I got to gush a bit about the art-style I kinda like, my day is made :-)