One of the less noticeable options in Diablo III is Elective Mode. While it’s not terribly important at first, Elective Mode becomes very useful later in the game once all the Hotbar Skill Slots are opened for your use and you have settled into your playstyle.
Many players will find themselves with one or more skills on their setup that they don’t use often enough to warrant their being present, but they don’t’ want another skill of the same type more than that either (My personal experiences with this highlight my Wizard’s Mastery slot and my Monk’s Secondary skill slot). This can be solved by the use of Elective mode, which is there for just such a purpose.
Lurking out of sight in the Options Menu, Elective Mode can be found in the Gameplay tab. Checking off the Elective Mode box lets you do something amazing.
It lets you put any skill in any skill slot.
This not only allows you to re-organize your skills, it lets you put any skill you know in any slot. If you really want to have all of your Primary skills take up skill slots on your interface, you can do that. If you really want to have no resource-generating skills available, you can do that (although why you would I can’t begin to fathom). Most importantly, you can replace a skill from a group that you don’t see yourself finding a use for with a skill that you wanted but couldn’t have had space for otherwise.
This opens up huge new areas of setup, and enables builds that would otherwise be impossible. Demon Hunters can use Evasive Fire, as an example, in the main mouse skill slot, and still have a Devices skill available in their hotbar- and it works, because Evasive Fire generates Hatred just like any of the Primary skills does.
The only true limitation on this is that you cannot have two versions of the same skill available- so you can’t, say, alternate Leaping Spiders and Spider Queen without actually going in and swapping the skills around in the Skills screen.
This limitation isn’t terribly big, however, so Elective Mode is an unqualified boon to all classes and all builds. If you’re having trouble doing what you want in normal mode, enable Elective Mode and go wild- you’ll find it helps you more than you ever imagined.