What I think they should do is to add an interesting affixes to every raid and dungeon.
One that does a partial buff if you play well, one that is just to add challenge.
NOT like the affixes in modern mythic +, but more classic style.
For Example,
Molten Core:
- All player buffs are dispelled upon engaging raid bosses
- Fire Damage increase by x1.5, Fire resistance also gives crit damage in the raid instance.
Wailing Caverns
- Upon engaging a boss players enter a dream state where they deal half damage and take 25% more damage until bosses health reaches 75%.
- In the dungeon Nature, Arcane and physical damage is increased against players by 15% and decreased against enemies by 15%, but these damage sources for players applies a stacking buff once per second, once buff reaches 20 stacks, next physical, arcane, or nature spell is increased by 300%.
Shadowfang keep:
- Bosses have haunting presence which alternates between decreasing physical damage by 35% or magic damage by 35% every 5 seconds. Holy damage is immune to this effect.
- Debuff effects are increased by 25% by all creatures and players in the dungeon.
Naxx:
- Sickness: players periodically are stricken with a random debuff in the game throughout the dungeon(lets limit this to all debuffs from lvl 20-59 mobs). The debuff automatically drops off if you are away from players by 20ft for 15 seconds. 10 debuffs go out every 30 seconds.
- Shadow and Frost damage increase by 20% to players. Shadow and frost resistance also gives stamina, mana regen, and nature damage in the dungeon.
Scarlet Monestary Cath
- MAgic resistence and armor are increased by 20% by enemies. Players are dealt 2% of their damage done.
- Spell damage from enemies crit is increase by 20%. When players are hit by holy or fire damage, their next ability is increased by 20%(10 sec cooldown).
one can only dream xD