There is plenty of variants of active and passive abilities in a game. The Rune`s system increases them repeatedly.
In this connection would be logical to create an additional panel in a game on that it would be possible to save personal builds, and to have the opportunity simultaneously switched between them by one button.
Yes, the idea is very viable. Being able to switch between at least 2 specs would be great. An important point here is to allow automatic runestone switching together with the spec swap. While speaking of swapping one thing i´m still missing in D3 is the hotkey weapon swap in the invetory. Hopefully they get this one back at a point.
They already changed the system so you could change a skill at any time, but after changing it, it has a 30 second cooldown and spells on cooldown can't be changed. Now a lot of people changes skills right before moving into the boss room. If that's the case than I don't see why a swap system would be bad.
Lets look at an example where it's also really nice.
Imagine your a mage and you have a really good build named X.
Now you want to try new builds so you start experimenting with a melee mage.
It turns out to be insanely bad and you have to swap all the skills back to the way you thought X was. If you could simply load X in a second that would save so much time.
Also Jay stated in an interview that when a rune drops it's a lvl X rune. But when you apply that rune to a skill it will become a rune ONLY for that skill. Now if you have 100s of runes later on it is really anoying to have to constantly swap 6 skills 6 runes and 3 passives don't you think?
I just don´t really understand the ppl who are against such a quick swap. The way the system works at the moment allows you skill swapping as well. So the issue with swapping skills just before a boss or some other challange and swapping back has already been solved with the 30 sec CD on skills. So I think it makes more sense pressing a button and getting your second spec and waiting again for 30 sec before you are able to use it, instead of spending time changing every single skill and every single rune to get the same effect ....