"Smart loot" in D3 was only needed because the drop rate of anything worthwhile was so low to begin with. Instead of "smart loot", they could have just increased the base drop rate enough to where you get just as much worthwhile loot for your current character (in a post-RoS world where all trading is banned, this wouldn't have hurt a thing). Then you'd still be able to get items for characters (classes) other than the one you happen to be playing at the moment - a very common Diablo playstyle that "smart loot" completely broke. "Smart" loot was a dumb way to fix the problem, and by the way, I have put hundreds of hours into D3 both on original release, and after RoS release.
Yeah, if your focus is on gearing up your alts without playing them, the Smart Loot system makes that very difficult (particularly if you're playing solo). But for people who want to focus on one character at a time it's a huge improvement to not be constantly receiving drops for other classes. There were few things more annoying than gathering up crafting ingredients (without the aid of the auction house), and blowing your resources on crafting gear that had a random assortment of useless stats for your build.
I don't know if increasing the amount of drops would have solved the problem, or if it would have just flooded my inventory with more useless items. They actually lowered the drop rate once Smart Loot was implemented.
