As much for my own reference when choosing new Talents in the new trees as anything else, here are the talent layouts I’ve been running with my Mains in Shadowlands — but really more or less since… when was it? Cataclysm? Mists of Pandaria?… the time when the three-talent rows were first introduced.
Elemental Shaman
Restoration Shaman
Balance Druid
Fire Mage
Frost Mage
Arcane Mage
Kamalia et alia 
I really should snapshot my UI today. That thing has evolved over a long time!
Yes, you should! Before-and-after is always a fun game to play 😀
I believe it was Pandaria. Sadly it will probably mean me looking at WoWhead or IcyVeins for a cookie cutter build. The last time I played around with picking so many choices made absolutely no sense and seemed to contradict what you were trying to build for.
Pandaria is probably right then 🙂
I’m going to try to not look for a cookie cutter build, but I might end up there eventually.
One thing I learned many years ago when I actually understood Shadowpriests and helped people was that there will be one set of choices that will out perform all others. Unfortunately now that involves having to play a specific convoluted way that requires a great deal of skill. You would think that they would have learned and given us a few options that are all viable, but that leads to too much tuning to balance.
Sadly, that is true — and I avoid having to learn that optimal, specific, convoluted way by not playing in any groups more challenging than Heroic LFD or the occasional LFR 😛
I do need to figure out how the recent click-casting addition to the default UI works if I want to get back into healing with Kamalia in Dragonflight, though.