A different kind of arena

OontzOontz - Dreamweaver

One where hp and damage are fixed.
Example
Starter skills = 100 damage
Level 9 skills = 150 dmg
Level 19 = 250 dmg
Level 29 = 400
Level 39 = 600
Level 49 = 800
Level 59 = 1000
Level 79 = 1250
Level 100 = 1500
Auto-attack = 1 damage, but a critical is 20 damage

Hp would be based on your level and your actual hp. It could be (Max HP x 20) / Level.
So a level 60 with 5000 hp vs a level 100 with 15000 hp, would be 1600 hp vs 3000 hp. The level 60 now has a chance instead of being one shotted like on the outside world.

All other stats, attack/defense levels and buffs wouldn't really matter except for hp and crit rate. It wouldn't take cash shopping out of the equation since refining your armor for hp costs more than refining your weapon.

Weapons are also mandatory. Skills would be disabled if you don't use the correct weapon with an equal or higher level requirement than the skill.