Potion buffs stay max lvl longer
Pots & cooked food weight reduced
Exp curve fixed, low lvls slightly faster, high lvls massively easier
Gain more exp in lowest cmb stats (the higher your other cmb stats). Gain extra hp exp for lvling lowest cmb stats
Experience loss on death reworked
HP loses 3x less exp
Repeated deaths are less punishing
Lvls not lost immediately on death but overtime
Lost lvls are easier to regain
Fatigue on death, regained exp is not given immediately but overtime
Exp is stolen from players on kill
If victim had 99 cooking but you only had 1 cooking when you killed them, you won't gain much exp
Stolen exp is increased if they had been leveling the particular skill recently
Can't steal recently stolen exp
Min HP from 10 to 50
Exp gain is changed, you instead are rewarded with genie lamps that let you pick from a selection of skills
Doing any combat style training grants you lamps to level any other combat stat
When you are a high lvl, you gain much more combat experience by attacking the highest level monsters
Ability to trade your lvls in one stat and put them in another (to lvl more optimally, respec or to change your combat level/acc build)

Cmb lvl formula reworked
Magic always increases cmb lvl
Dmg calc reworked
60 attack 99 strength vs 99 attack 99 strength: both players will max hit eachother just as often, but the 60 attack player will hit lower hits less often
Gear rebalanced to promote risk over stats
99 defence wearing full addy is worse than 40 defence wearing full rune
99 attack using rune scim is weaker than 60 atk using dragon scim
Melee formulas changed to accomodate more builds
Defence first reduces enemy accuracy. If you have particularly high defence, instead weakens damage curve so enemy max hits less, rather than stopping most hits entirely
Against low armor/low defence opponents, 99 attack 40 strength will be better overall dps than 40 attack 99 strength
If you have low strength but a good weapon, you will have reasonably high max hits. especially on slow/2hers (KO weapons)
Ranger armor reduces the frequency of high/max hits from melee attackers, and even more from magic attacks. Ranged armor is adequate defence from low damaging ranged attacks (darts and knives in particular).
All gear degrades, particularly from death.

More cookables eg dragon meat
New variants of CC and reworked CC
Melee dmg reduces accuracy of next spell cast
Remove crush/stab/slash
Higher lvl spells are less accurate
Defence prayer buffed when wearing low armor/low def lvl
Drinking potions buffs last longer the higher ur herblore lvl
Prayers with multiple tiers (e.g. super strength, ultimate strength) simplified into one prayer that scales with prayer lvl
You always have a looting bag, not lost on deaths. You can interact with some items in it, like uncooked food which can be cooked and then is put in your inventory.
Runes take up zero inventory space
Bank keys reworked
Whenever you loot or acquire an item, it is temporarily "bank loot" for anyone who kills you in PVP. ie if you farmed 2 inventories of green drags in the past hour, then when you die even if your inventory is empty you lose all of those items to that player. All personal loot is therefore temporarily 'untradeable'
Skulls above heads and bank keys above heads are removed
Players prayer bonus reduces the effect of Smite
Defence level no longer provides magic defence
Magic level no longer provides magic defence

Interface improved so you can see prayer, inventory, spells, specbar all at same time without need for f-keys
Poisons apply heal debuff, reducing food healing
Each hit to someone who is frozen reduces the remaining duration
Rangers can throw a net to freeze their target in place, no spec required
Melee can use clubs to freeze their target in place, no spec required
Ice barrage downside: increases victim's defence
Net downside: breaks faster from damage
Barbed netting: damages the enemy if they move when it expires
Time bomb spell: if the victim receives enough damage in the next X ticks, they are hit by the spell
Channel spell, deals damage each or every other tick several times. If you splash once, the channel ends. Moving ends the channel. The first tick of damage is instant.
DoT spell: deals medium damage and then deals extra damage each tick for X ticks
Mage armor spell: increases your physical defence until you take X damage. doesn't stack with regular armor
Saradomin brew nerf: reduces max hp per sip. doesn't increase defence
Remove pid so pvp is not biased/unfair
Bad RNG protection, so its impossible to splash too many times in a row
Fun map pickups e.g. wilderness weapon spawn that is picked up and degrades in 30 minutes even if not used. Can't be banked.
Rebalance to unused weapons in PVP eg longbows
Purge mechanic. Every hour or two hours the purge starts. Non-wilderness areas become pvp zones, with exception to banks. Teles will put you in banks if used during purge. If you are still in combat with someone at the end of purge, you can continue to fight