Originally posted by Pandarandrist1
Devs have responded to this suggestion before. IIRC, they basically said, "This is an interesting idea but one we generally scrapped because it dilutes the affix pool far, far too much. We have other ideas for itemization down the line, and we are very excited to show them to you, when the time comes".
Just doing my best here, /u/ekimarcher
I think the reason I've given in the past was more along the lines of that we didn't want to have an affix that says "+3 to Fiery Temper" and then you're like "well, wtf is that?". You hold alt and it explains that it's a passive in the sorc tree at req 45 points or something (fully just making this node up). Then you have to go into your passive tree and look up what it does. This knowledge dependency chain is something we like to avoid as much as possible.
Then on top of that, you have to figure out if these points count towards getting to the next section of your passives, they wouldn't, but then you're adding up points and these extra points are confusing. Ugh, just a mess. Oh and also, what if you're playing as a rogue when the item drops, you can't even look up in game what it does.
It makes more sense to us to just put the effect of the node on the item as only a select few would be good to do this for anyways.