That's the point though isn't it, it's the people that face things well below a challenge, overpowering the area which is no challenge.
I've already seen people with hand-me downs or twinks with race specific items they've garnered from another character rush through zones atomizing everything in their path. No fun for anyone else in the party, watching them one-shot everything with no risk of injury. The watchers barely get to participate at all, and it's a huge turn off.
The should have a "super elite" for those people which is +5 levels above the base quest. Instead of just the +2 that the current elite is.
Maybe just making hard +2 levels and elite +4 levels would do it.
I'd much rather see clever tactics , well thought out plans than a zerg rush , any day.