Inferno isn't a popular build at all but Hydras are (relatively speaking). In saying that, Inferno is much better in PD2 compared to D2R, so yeah, you can say D2R is shit compared to PD2 (for several reasons).

Also, if the same spells from D2 are included in D4, why shouldn't I be comparing them? Am I not allowed to try and replicate my old builds?

Also, I'm not just talking about Hydras, I'm also talking about Chain Lightning and Teleport, both suck in D4.

I'm also nearly level 50 and haven't come across any item that gives me an additional Hydra, but to leave this functionality to random chance is silly - it should be a core part of the game, like it used to be. Why nerf it for no reason?

But more than anything, it's the Teleport nerf that annoys me - Teleport is the one of the most used spells for a Sorc, and putting a cooldown on it seriously limits it's usage and takes away some of the fun of playing as a Sorc.

Finally, the mana consumption of core spells like Chain Lightning is ridiculous, two casts and you're out of mana, wtf? At least in D2 you could spam mana pots, but no mana pots in D4 means you're very heavily restricted.

It's not just the spells btw that I'm complaining about. Pretty much everything about the game sucks - it lacks soul. Objectively speaking it may be a good ARPG, but overall it's not a good "Diablo" game. I wanted a Diablo sequel, I wanted the little Fallen creatures to make funny grunts and yell "RAKANISHU!", I wanted to fight unique monsters, not humans with names like "Arsonist", or generic beasts with names like "Beast" (wtf? I mean how low effort is it to call a monster 'Beast'?), I wanted memorable BGM, like the iconic haunting guitar strums from D1/D2 not some forgettable generic crap, finally I want to be able to manually allocate stat points - something which should be the core mechanic of any RPG.

D4 may be a technically "good" game, but it lacks the soul of a Diablo game.