Just wanted to highlight this because it is kind of the truth.
For my Druid (s0) and Necromancer (s1) I did build those guys out from scratch and played them. Druid was something pretty close to Lightning Shred and Necomancer was just CE Necro which was a fairly obvious build from the get go. In s2 since I was playing Sorc, which isn’t a class I normally play in Diablo games, I just researched builds around my favorite spells after trying a bunch of stuff 1-70 and settled on CL as my favorite spell and built that to around max that I could while making some slight changes.
Post Tal’s, due to damage-type stacking though, I’ve joined BL because the gap widened even further. I’m almost done with s2 though and then I’ll jump onto Eternal Realm and work on my Druid and Necro again =)