ps>This is just a draft, so some didn't completed yet, but I'll give some details later
Some game mechanics for difficult challenges
Many aspects of DDO are too easy now.
Many people suggested lowering power creep AFFECTING ON TOON such as removal of PRR, MRR, displacement, etc.
But, I think that might just bring OP classes from A to B. Like from melee classes to ranged classes again.
So, I suggest some fundamental game mechanics AFFECTING NOT ONLY ON TOONS, BUT ALSO FOR PLAYERS for more challenges.
1. Confusion spell against players
Reverse key bindings when you are affected by confusion spell. If you run forward, your toon will run backward.
If you turn right, your toon will turn left. Vice Versa.
Smart players will adapt to this confusion spell. But, it brings some challenges even for them.
2. Damage Reflection aura or area
When some mob activates its aura(you can see it visually), your damage will be reflected, so you will be damaged by your attacks.
The harder you hit, the harder you will be damaged.
The aura turn on & turn off periodically.
You should stop DPS when it on, and start DPS when it off.
Auto attacking only means death.
3. PRR/MRR penalty based on number of active aggro list
To prevent mindless displaced high PRR/MRR high save cleaving zerg runner.
If you have 10+ mobs aggroed, your PRR/MRR will be lowered by 0. They will hit you always with full power.
4. More no save CC spells against players
If you have insane saves, you can just ignore most of CC. Yes, you can raise its DC, but some builds will have more saves.
So, raise usage of no-save CC spells, like otto's irresistable dance, otto's whisler for ranged mobs.
5. No PRR/MRR against trap
6. Percent based damage that ignores PRR/MRR
Current damages from mobs threatening only low PRR/MRR + low hp players much.
Imagine when you are in ToEE 2 end boss room. The boss cast hellball & constant DOTs from mushrooms, high PRR/MRR, high hp toons can almost ignore that damages easily, but, low PRR/MRR + low hp toons have huge threat from it. Dodge, evasion doesn't work against it. So, change such attacks have percent based damage(5% of max hp per stack) that ignore PRR/MRR would be threat regardless of classes.
7. HP/SP exchange between players
8. PRR bypass for rogue / ranger type mobs
9. Lowering effciency for AOE type attacks
Making Improved Precise shot like Glancing blow, Raising effeciency for Archer's focus
Full damage on 1st target, but no additional damage(like weapon proc) on passing through shot.
Archer's focus stacks up to 10 times, but each stack gives you +5% bonus damage
10. Removing immunity against negative damage spell for Deathward spell
Currently, negative damage spells are just useless, because Deathward spell can block it completely.
So, you can just ignore those threats when you have deathward.
Make deathward to give some damage reduction against negative spells. Like 30% reduction stacking with deathblock reduction gear.
This one will also open up new viable build on player side :
Negative Nuking Cleric or Pale Master, maybe Favored Soul(But, I think light/alignment based nuking is better-fitting for FVS flavor)
And, we need some ED that support Negative DPS, there is no ED that supports Negative DPS.
Battle against drow priestess, vampire will be real threat, not boring fight.