IDK, from what I saw in alpha and beta footage it looked incredibly fun… something changed since then and I suspect that something was ‘balance’. Elite mobs got their stacking damage buffs which also made them immune to CC (though now removed) and the amount of powers on offer from any given orb are drastically lowered.
Bit of a bait and switch. Ironic since those same videos also reported that Blizzard were excited that they had a potential homerun with this game mode… key word was ‘had’ I suppose.