Thanks for the welcome!
Now I have been giving this some thought, for my sorcerer and assassin at least.
I'm basing this from looking at a unique and set item list. It looks like there's unique rings that would provide a huge benefit but no strength bonus, so I don't want to rely on my ring slots for that. Mara's Kaleidoscope looks like it might be the best amulet for him and that's 10-20 to all stats.
Now, looking at the strength requirements on various pieces of equipment, there's Tal Rasha's, the most costly of which requires 70 strength, but the amulet provides +10 to all stats, so I only need 60 base strength to have the the freedom to wear any rings I want. There's also a unique Archon Plate with a requirement of 70 strength and, if I'm counting on getting Mara's Kaleidoscope, I only need 50-60 base strength. It looks like 60 base is the minimum to go for.
There are other pieces of equipment to consider though. The highest level unique staff requires 96 strength, but has +10-12 to all stats. I could get by with 84-86 strength on that basis alone and, if I throw in Mara's Kaleidoscope, it's 64-76. I don't know if the Vile Caduceus is even the best option, but if I go with a one-handed option I have a shield to consider. None of the unique shields seem to be worth the strength investment though. The heftiest strength requirement of anything I would actually want to wear is from the Crown of Ages, which hardly seems worth 170.
I'm even less certain about my assassin, though I do have some thoughts. If my idea of stacking elemental damage and spell procs is correct, then none of the best jewelry I have in mind will give me any strength bonus (Highlord's Wrath, Raven Frost, Band of Elements). I almost certainly want the Dragon's Breach shield at 121 strength. For my weapon, I'm looking at Blade of Five Suns (187 strength), The Vortex (130 strength), and Schaefer's Hammer (179 strength). I'm leaning towards The Vortex due to the lower strength requirement and combination of elements, but it has no penetration! And if I want to wear the Crown of Ages, that's 170. My assassin all has much more ambiguous armor and belt choices compared to my sorcerer.
For Barbs you want to STR because of their abilities. DEX becomes important once you start missing, and VIT is only for survivability.
For Warriors it's the same game plan but your DEX becomes more important as the game goes on because that's the stat tied to CritChance%, and that becomes more important the deeper you go. Warriors don't get the same Ignore Target Defense god-tier gear that Rogues do so a lot of times the crits are the only way to take down some of the higher-level bosses.
I thought barbarians and warriors were the same in this respect. Do they not get the same effect from dexterity or use the same weapons effectively?