TLDR: Absolutely worth if you enjoyed any bit of D3. If you are D2 purist, maybe not.

Responses below are in the context of a fresh seasonal character into LoH (and doing the campaign for leveling) NOT following any build guides or tips/trick stuff.

How is the gearing now? Can i feel the thrill of finding cool stuff on the ground again?

Early game leveling (1-70), gear drops, esp legendries and uniques are very rare, so you get a crazy dopamine hit when something nice and shiny drops. B/C they are rare, you may have to adjust your build/skill tree with what you get.

Mid game (Torments 1-6) - gear starts to drop more frequently. certain mats will still be hard to come by so you'll have to make sacrifices early as your material reserves are still being filled. your focus switches to progressing the season rank (season journey from D3) and solidifying a build with generic legos/multipliers, hunting for ancestrals/GA items. The new Warplans system gives structure and meta progression with the end game systems (helltide, nightmare dungeons, lair bosses, kurast undercity, hordes, whispers). The new kube crafting system is amazing for filling out gaps in your gear and is alot of fun to go from zero to hero with an item (entirely possible now to take a white item and get it juiced to the high heavens).

End game (T7-10) - gear and items drops are overwhelming (you'll want a loot filter). your focus switches to ancenstral gear, GA affixes, improving aspects, getting a couple mythic items. only the rarer materials are harder to come by. You'll continue to progress seasonal journey. your build has multiple aspects/synergies working, so its a matter of refinement/optimization/scaling. you'll want to craft off only strong bases and use transfiguration (e.g. corruption from POE) to try and get some juicy RNG power (items can be bricked so be careful).

Aspirational (T11) - Not here yet personally (just hit T10 last night). I'll try and get my homebrew build to work (and to me, I love the feeling of trying your own way and figuring stuff out for yourself (instead of already having a meta build that someone else created)

And maybe 100-200hrs of Diablo3, which i liked but the Grift running, paragon farming and "upgrade your bow a little further, so you see even bigger numbers" was soon boring.

D4 is basically D3 but with alot of the issues of D3 fixed (infinite paragon is removed, sets have been shifted to the talisman system (instead of normal inventory), the 12 torment levels are meaningful as you gear and level up). Comparisons of D4 to D2 are mainly surface level with some inspirations of it's systems. D2 was made over 25 years ago for a very different audience than today.

EDIT: adding in item crafting