OK. I have built a L70 Necro. By way of introduction, I played D, D2 and D3/LOD for about 10 years. Then my wife introduced me to WoW, which I've been playing for the last 5 years. However, I didn't enjoy anything about Shadowlands so came back to D3.
I'm looking for a couple of things:
One, I have always played solo but find at this level I need a playmate. So if anyone out there is interested, drop me a line (Spoiler: I am an old guy but I love the game); Two, I want to discuss ideas about the Necromancer build, I don't understand how some of the skills work. I currently have (1) Army of the Dead, (2) Bone Spear, (3) Corpse Lance, (4) Command Skeletons, (L) Grim Scythe and (R) Siphon blood. It's a powerful semi-melee/ranged attack. It's worked well but I'm into Greater Rifts now and while I can complete them I don't get thru fast enough for the big rewards. So I would like someone to suggest if and how I can improve the build to address this (and why this will work better -- that isn't a challenge, I just need to expand my education.

I am going the corpselance support build for Necromancer and the build has me taking Corpselance with Brittle and the pestilence set on top of that, if I were to take off the ability Corpselance and change it to another ability say for example Bone Spikes with Frost spikes, would the damage decrease an amount that it would not be worth it?

Alright my first build... Here we go!
Now Necromancers aren't my 'main' classes but i play with them and im pretty good with them. And i come up with a build that is a bit boring, but ultra powerful, so lets begin!
1. Primary Attack, Primary attack should be bone spikes with the rune: Path of bones or Blood spikes. Why? Blood spikes are for people that lose health really quickly, and the blood spikes allow you to heal over the bleeding enemies you hit. Path of bones on the other hand is for people who have a lot of enemies in your way. Or you can have no rune, which i mildly recommend for people who are already strong just want to be a bit stronger :))
2. Secondary Attack. Should be Bone spear with the rune: Teeth or Blighted Marrow. Teeth is the one that i recommend for most people to use, why? Teeth fires more bone spears trough enemies, of course it deals not much damage but it damages more enemies. Plus, you can get an achievement for killing 40 enemies with bone spear within 3 seconds. Bligthed Marrow is for people that like to stay behind their minions and just fire their bone spear trough enemies. I call this build the lazy one. 
3. Corpses. Should be using Corpse Lance with the rune: Ricochet. Why? Ricochet allows you to have an chance to hit one more bonus enemy when you attack the first one. Which is pretty good.
4. Reanimation. Should be Command Skeletons with the rune: Kill Command,Frenzy and Dark Mending. Kill command is for people who are confident without their minions and want ther minions do yeet themself to enemies and kill them in one shot. Frenzy is the one that i recommend the most, this will allow you to command your skeletons to gain attack speed (which means more damage to the enemy) and it's just really that powerful. And Dark Mending is the last one. Dark mending is for people who lose health pretty quickly and want their minions to heal them.
5. Curses. Either Frailty or Leech. Frailty is for people who want their minions to deal much bigger damage with the rune: Scent of Blood. Why? Scent of blood will allow your minions to attack 15% increased damage, which is really helpful if you want your minions to do the job and not you. Leech is for people that lose a lot or a bit of health. With the rune Sanguine End. Cause it will allow you to heal 200% for the enemies that die.
6. Blood and Bone. This should be RIGHT OF THE BACK bone spirit with the rune: Poltergeist. Why? Bone spirit is powerful as heck and you should use it immediately when you get it. The rune Poltergeist will allow you to have 4 bone spirit, which means EVEN MORE DAMAGE THEN BEFORE HAHA.
7. Passive skills. I recommend: Overwhelming Essence for people that want more Essence and use a lot of Essence now and then. Spreading Malediction is for people that want their curses to deal a lot more damage, well not much but 1% increased damage is at least okay. Serration is also a really good passive skill, Serration is for people that like to stay behind while their minions do their business and you like to stay behind and just shoot bone spikes at them. And finally Aberrant Animator. For people that like to increase the thorns damage for their minions
And that's it! Took me a lot of time, and some repilies and thanks would be appreciated. And yeah, hope you are good with your necromancer now!
OH sorry if the text is black! I didn't realize that it would be hard to read on my post, cause when i m editing it looks white so... sorry :((

I came to Icy Veins to setup my Elemental Shaman only to find your Talent setup does not match what is offered in the game presently.  Below I have listed what I see in my current in-game talent setup and bolded those items that do not match your setup at all.
Current in-game Talents listed:                                                   Your Listing:                      
15 Exposed Elements Echo of the Elements Elemental Blast               Earthen Rage 30 Aftershock Master of Elements Totem Mastery       Call the Thunder 45 Spirit Wolf Earth Shield Static Charge         60 High Voltage Storm Elemental Liquid Magma Totem       Master of the Elements 75 Nature's Guardian Ancestral Guidance Wind Rush Totem         90 Earthen Rage Primal Elementalist Icefury       Surge of Power 100 Unlimited Power Stormkeeper Ascendance         I thought someone here should know about these differences because it appears there has been no update recently to your setup.   I know that I personally would appreciate an update so that I can adjust my in-game setup to work better.

I usually sim my characters to get the best possible results. I enjoy the process quite a lot and since I reached 120, I wanted to find out the best build of the spec. (Note, I didn't want to find out what to play, but rather how my own build fares in comarison.) I rarely mind a 1-2% difference. If it goes above 2%, I really mind a change. What this thread is about is mainly to bring something in the attention of those who help making the class guides, especially the talent choices. To my surprise, I was awed to find out that certain talents outperform previous "Standard" choices in the endgame, probably due to the stat squish.

The Frost go-to build (top dps) would probably be along the lines of <Icy Talons / Cold Heart - Runic Attenuation - Frozen Pulse - Gathering Storm - Breath of Sindragosa>. What I found out primarily was that after the removal of legendaries, Cold Heart severely underperforms at most given situations resulting in a major dps drop due to the low mastery. Gathering Storm also suffers from the same problem and most of the times, Frostwyrm's Fury is better overall. The biggest surprise of them all, however, was that Inexorable Assault overperforms quite a lot, and is the first reason why I made the topic. I then started simming with the above in mind and I came across a build that some would not consider on par with top dog builds around the meta, which is the use of Horn of Winter which overperforms both its other two options when using the Breath build. Talent Sim can be seen here. Another intresting thing, which I loved, was that the 2nd best build uses Obliteration as a lvl 100 talent and no other build surpassed it (Other than the first one, obviously). So, I encourage frost players out there to give their other, less common talents a try. To the class guide author(s), I believe that the two "underdog" talents will earn their spot in the class guides.

Thank you for your time reading this.