Champions are a bandaid fix in a much larger problem, player power creep. FotM builds have so much power in them that they simply don't allow monsters to get off 2-3 attacks before they die. Simply buffing enemies will make the game impossible for those who have not yet reached that power level. Toning down FotM builds, reducing the availability of instakill mechanics to players and toning down all self-sufficiency for damage-oriented builds should be at priority, but those would cause more anger amongst the playerbase.
Check items. Some items have budgets too high for their level. I take a very random example from U28:
Epic Ship Kickers. Ins Dex +4 is definitely a +4 budget, if not higher. Riposte X is +10. Balance +20 is +10. Yellow augment +2, Green +3. And I'm not even including the set bonuses or possible mythic bonus. If such item dropped as random treasure, it'd have min level of 57. Or let's check
Fellblade. +13 Enhancement is +13. Improved Banishing definitely at least a +4 (oh look, an instakill property). Sovereign Vorpal at least a +1 (oh look, another instakill mechanic). Axiomatic X is +10. Armor-piercing 20%... shall we say +2? Doublestrike 15% is definitely +5 at least. And +5 from augments. That's an item with +35 value when I've assigned outstandingly low budget values to some of its properties. Granted it comes from a raid, so it has to be more powerful than other items of its level. But look how much more power it grants! This is an item that even with Wondrous Craftsmanship, +2 Jewel, Guild bonus and Greater Dragonmark of Finding, you wouldn't see it drop in anything below a lvl60 quest. Or if we try to put it in other words, its an item designed to be used against CR 70+ enemies. What CRs are you fighting in EE quests? Highest I remember seeing is 69.
When they design the game to give extraordinarily powerful rewards to players, it should be of no surprise that content is roflstomped. Changing current content to accommodate this player power creep will only make it unbearable for those who haven't reached that point in power creep yet. They need to release new content to challenge such players, but that new content will have to also reward even better equipment. Which means even higher player power against previous content. Turbine let scaling go out of hand, and now they can't keep it in control.