Well, the idea I had suggested to nevo long ago was thinking of a kind of new elemental stone.
Since we already have an offensive item, we could have a second one for defense.
The idea was for a new achievement and the new stone would increase defense, but it also involved creating a new mode and a new boss...
I had all sorts of ideas, but they were kinda hard to implement because almost all of them needed new modes aside from already having to create the new items...
Changing a little one of the suggestions I gave nevo before, you could actually change the Orbs and make them usefull
Currently the Items associated with the Elemental stone have passive damage and increase in stats attribute.
If possible, add another passive to the list making use of the Orbs.
Example: Elemental Stone + Blasting Staff = Ele Staff + poisonous Orb = Poisonous Ele Staff ( that adds a passive poison ability that already exists in wc3, it would only need to be balanced to the game. )
Such other abilities associated with the orbs are all within the game, I just dont really know how much work it would need to implement