Having played some more...
1) The game does not have the technology to properly convey champions. Target -> Examine -> Mouseover is fine for communicating detail, but can not tell a player anything rapidly in the real-time adventure of DDO. There's a reason that we see the "True seeing" or "Freedom of Movement" icon on cast, why "blur" has a model effect, why Jariliths show they're activating Power Attack... (Corollary to this: the Epic Ward icon hovering is meaningless now, and is too easily confused with Death Ward.)
Players learn from the environment, determine patterns, and calculate strategies on the fly. They learn how to deal with "casters" and "melees" and "archers" through play. Giving buffs and debuffs that drastically alter the way a player handles an encounter, outside of their expectations, is not 'fun'. To cite the Extra Credits video posted earlier in the thread: You're breaking your own rules.
Since Champions are more common than the uptime on my CC abilities, I'll either waste time, not playing, not having fun, waiting to research the critical information you have failed to convey, or I'll just hope for the best and keep playing.
2) On-Hit effects are broken. They are indiscriminate. They seem to just hook onto the hit-proc, without determining whether that function would do damage. I've encountered Water Elementals that had On-Hit: Lightning effects, and dealt 200 damage a tick because their "Freezing Spray" debuff kept "hitting" me. Also, these effects seem to be X damage of random damage type, and the list includes Light, Poison, and Force damage. These types are irresistible. While the Lighting proc may (though I'm skeptical they actually do) be mitigated by MRR, taking the full X damage as Poison is excessively harsh. While I'm really only checking the champions that hurt real bad or kill me now (so I can't say for certain that I'm not ever getting, say, On-Hit: Fire that raises an eyebrow), it feels like this is like the inverse of the Celestia DR issue... When giving celestia +1 or +[w] forces its damage to go through the DR engine, it feels like these On-Hit effects force the mobs' hits to bypass the DR engine.
3) True Seeing is far too common and penalizing for lightly armored character types. Light Armor gives very low PRR. Bucklers give no PRR and no MRR. Arbitrarily negating half of my defenses, compounded by the On-Hit effects bypassing another major aspect of my defense: saves, just makes for a highly punishing play experience. The result is that "squishies" are penalized more than the "tanks", who still have their AC and PRR to protect them. (How soon would the lynch mob arrive if True Seeing cut PRR by 50%?)
4) Epic Ward still sucks. CC is more important to deal with the new champions, but Epic Ward limits charms. If you want me to use more of the tools at my disposal, don't nerf them. Inducing Helplessness via stat drain should be a viable tactic to deal with the mountains of hp Champions. Etc, Etc...
5) This implementation is all stick, no carrot. I "get" that it's supposed to be an adjustment to difficulty. Chests only from Orange names, containing only vendor-loot, is not rewarding. The following suggestion is probably too deep into "overhaul" territory to get implemented, but, here is my "carrot":
Each Champion kill adds an amount of Base XP.
First Run of the Day bonus remains.
First Time difficulty Completion remains
Bravery Bonus remains, but probably should be adjusted downwards slightly.
Bravery Streak goes away.
For example, suppose the Base value xp was calculated as arbitraryBaseValue(=4) * qLvl(26) * difficultyModifier(=h2/e3) -> 312 xp per champion slain to the base XP awarded by the Quest... Then all modifiers (ship, VIP, tome of learning, pots, First Run, etc) scale it up.
This incentivizes the harder content. Allows a player to jump into a Normal raid no-harm-no-foul, complete the content they want at their own choosing (I love the Harbinger pack, but we usually skip In The Flesh instead of break streak... It'd be nice to drop down to hard for just that one quest...), facilitates grouping (no harm in joining a pug without the streak to maintain), doesn't promote TR over ER (grinding out ERs without streak gets tedious).
Net result can be an increase in difficulty/progression, but still gives players a reason to want to engage Champions.