Are there any games like Diablo but not Diablo because Diablo?

Grim Dawn is "What if a sequel to Diablo 2, but not Diablo 3?"

Oh? I've only actually played 3 so I have no reference to 2 and what the differences are
- Old timer here.... Diablo 2 has a story with an atmosphere that sucks you in. In that sense Diablo 3 was a real disappointment.
  
  Now, if you're going for Diablo 2 it's the remastered version you want. The game is like 20 years old and not made for widescreen so it really feels dated on a modern screen. Also, prepare for isometric pixel graphics.
  
  Grim Dawn also has a mod called Reign Of Terror that lets you play the entirety of Diablo 2 in GD, complete with classes, skills and items! It has some differences because it's built on Grim Dawn's systems, so it has the dual-class system from Grim Dawn (with similarly laid out skill trees), item affixes work like Grim Dawn, etc, but it feels great to play! And you can combine Grim Dawn classes with D2 classes, D2 classes with other D2 classes, or just play the D2 campaign with a regular Grim Dawn build. It's great!
  
  EDIT: spelling
  
  Omg how have I not heard about this. I'm blaming you for my lack of social life in the next couple weeks. Not that I have one to begin with.
  
  I'll see you at the end of Act 2 when you remember what a fucking slog Act 3 was and decide you've scratched the itch.
  
  I'm now just learning of this too and intend to do the same
  
  Act 3
  
  Those fucking demon pygmies! Whenever I played necro, I always corpse exploded all of them
  
  Thanks for this!
- Another option is to get Grim Dawn, and then get the Reign of Terror mod. It's basically Diablo 2 recreated almost completely + some extra content.
  
  But since you've never played Diablo 2, I'd recommend playing it first in some form (D2R or PD2) so you can appreciate the storyline (and the epic cutscenes) - and then play the Grim Dawn mod.

Grim dawn looks cool aesthetically and I'm liking the UI and how big the skill tree looks. Are any of the expansions any good?

Absolutely. All of the expansions are good, but especially the ones that add extra masteries (classes).
All of them, honestly.

The Crucible is the weakest - it's just an arena mode, but it's got a lot of utility for speed leveling new characters + some QoL for existing ones.

Ashes of Malmouth is the direct continuation of the base game's story, adds Necromancer and Inquisitor which are both very well-loved masteries, and you need it for Forgotten Gods anyway. The zones are a bit meh - great overall mood but you spend a lot of time in cramped corridors.

Forgotten Gods adds Oathkeeper (very fun) and tons of huge new zones with a refreshingly different vibe to the rest of the game. And you can go to this expansion's zones from the start! (Except that you probably shouldn't on your first playthrough, you'd get destroyed and you probably want to focus on the main story anyway.)

I'd wait for a sale and get them all if you like this genre, or just base game + AoM if you just want to give it a shot (and technically you could hold off on AoM until you're close to the end of the campaign).

How would you say Titan Quest compares?

i only played a little of both. i like titan quest for the story and mythology, but grim dawn seems more refined and modern, it's actually by the SAME team (today i learned)!
- Yeah, that last part I knew, but I started diving into this genre with Titan Quest because the sequel is allegedly coming out this year.
  
  The Titan Quest sequel is being done by a completely different team, no guarantee it captures the same magic as the original.
  
  I'm aware, but it will likely be mechanically similar. If it turns out to be a Bloodlines 2 situation, I can always just stick to the first game and Grim Dawn, maybe V Rising. And all of that is assuming that as I spend more time in Titan Quest I still enjoy it.
  
  forgot about that, I would personally wait for the sequel but the first game is cheap anyway
I enjoyed Titan Quest more, but that may be down to the less grimdark aesthetics. Gameplay wise they’re both fine hack ‘n’ slashes.
Haven't played it. My progression was Diablo 2 -> Torchlight 1 and 2 -> Grim Dawn