I've recently added a comment to another post, but I decided to create a new discussion, as I think this topic needs more attention. So, why Necromancer is the worst class?

1. Necromancer is clunky. It has too many abilities with short timers to balance; you need to play necro like a piano to make it work (and now compare this to the beam bzz-bzz, all dead around arcanist).
2. Necromancer skills are just lacking. You need to add so many skills from other trees to make it work; it already doesn't feel like playing a necromancer. I recently decided to compare how many class skills I'm using on my PVP toons, and it's 10/12 for Nightblade (which speaks about how well NB skills are built to synergize with each other and give NB everything they need, like necessary buffs/debuffs, burst heal, heal over time, stuns, almost everything), it's 9/12 for DK, 8-9/12 for Sorc, and 5(!)/12 for Necro.
3. Speaking about Necro skills, it almost lacks everything:
a. Spammable? The Scythe lacks damage; you can't use it in competitive PVE, and almost no one uses it in PVP. The Venom/Ricochet Skull also lacks damage compared to other classes AND is bugged in many occasions, which has been reported on the forums/in tickets multiple times, but guess what? Never responded/confirmed/communicated.
b. Stun? No reliable class stun. Actually, now thinking about it, I've played this game since 2016 with some pauses in between, and I've NEVER seen anyone using Grave Grasp skill both in PVE and PVP; this can tell you how badly it is designed.
c. Corpse mechanic skills. They could be good, but in general too clunky to always reliably use. Good PVP, for example, relies on good knowledge of how to LOS when outnumbered/out of resources, which means most of the time you can LOS from your own buffs/tethers (Arcanists laugh with their crux system that reliably works all the time).
d. Necros have the worst Armor buff out of all classes. Nightblades have major resolve built in as a passive, so they don't even need to slot a certain skill to have 100% armor uptime. Other classes have some other utilities built into the armor buff, like DKs having either an AOE dot or a good shield. What do Necros have? Compared to other classes, Necro's pull mechanic is bad (not for tanks, but in general), and reducing summoning abilities is not that noticeable.
e. Ulties. You have Reanimate that could be useful in some scenarios, but has the highest cost out of ALL ulties in the game. The blastbone version of it is bugged and doesn't work properly all the time, which of course has been reported and never addressed. Colossus was good when it was first released. But they nerfed the vulnerability debuff and introduced other sets that provide this debuff, so now the Colossus is actually mediocre.
f. Blastbones. My most raging topic. The skill was always a bit clunky from the start, but it was the best at providing the most damage for necros. What they decided to do recently? Delete the best morph and replace it with an absolutely disgusting buff (2.5 seconds, you can LOS from your own buff, it lasts for 20 seconds, stopping your corpse generation, etc.). Did they listen to the feedback from players? No. Did they listen to the feedback after it was released (there is a topic with voting and 90%+ players would prefer to use the deleted morph)? No. They don't know what to do, but they are too stubborn to listen to players and revert the changes.
g. Gap closer? Doesn't exist for Necros.
h. Any skills that buffs other group players (like minor crit for sorcs/nbs, minor damage for dks/templars)? No.
i. Passive synergies? Necro has a passive that buffs DOT damage, but doesn't have skills that DEAL DOT damage. This is laughable how bad the design of the class is.
j. Maybe you want to feel like a true Necromancer and use some summoning skills? Well, the Skeletal Arcanist/Archer is one of the worst skills in the game. Can you imagine that it was nerfed like all DOTs were, but it's ACTUALLY NOT A DOT. You can compare it to Flames of Oblivion skills from DK. It's the same direct damage that fires to the nearest enemy, so you can't control it. Was FOS nerfed as a dot? No. Was Skeletal Mage nerfed as a DOT not being a DOT? Yes, obviously. I've already talked about blastbones above; let's skip it. The only OK summoning skill for necros is the Spirit Mender, so we have at least something.
4. Buffs/debuffs. Here is an old thread from '22 with class buff/debuff comparisons: https://forums.elderscrollsonline.com/en/discussion/618634/class-access-to-named-buffs-debuffs/p1 . Necros have 10 in total, nightblades 25, wardens 21. And we are not talking about small buffs/debuffs here. Necro doesn't have class access to major brutality/sorcery, major savagery/prophecy, major/minor expedition, major/minor evasion. All of this you need to compensate by slotting specific potions/skills, which in the end makes necros an abomination of itself having most of the skills outside of the class toolkit.
5. Bugs. Necro is by far the most buggy class and some bugs are there from their release till now, never addressed, never confirmed, always ignored.
a. Blastbones not reliable all the time, sometimes staying in place until cooldown ends.
b. Skull being buggy and sometimes not firing on a third cast.
c. Pets/summons not counting as pets, not benefiting from passives, etc.
d. Pets/summons not counting towards Battlegrounds stats, meaning necro is almost always in the last place when counting its damage/heals. Blastbones damage is not counted, Spirit Guardian heals are not counted, which discourages people from bringing Necros to BGs.
e. Corpse mechanic being bugged. Currently you can see the corpses that weren't killed by you, but you can't interact/consume them. It's fixed on PTS by actually removing the corpses, so you actually can't see them anymore. Again, thank you ZOS for the great solution; let's fix the problem by hiding it!
6. Necros don't excel at anything. PVP? Worst class by far, can't even compare. PVE? Necro is OK-ish DD (nightblade is worst by far, in comparison), but it's definitely not at the top. Necro is mediocre healer. Necro is a good tank, but in the current meta it's outshined by DK (always was) and by Arcanists.

There are other things, but I've already written so much that I can't remember.