Been playing a while now thought I would share some of my experiences.
Protection prayer do not fully protect you. Praying melee at dark beasts for example you still take damage.
When using the 'View Drop Table' option on any NPC, it will act like the 'Walk here' option and you will walk towards the NPC with the droptable screen open. Incredibly frustrating because when you walk to the NPC it will often attack you and close the drop table screen.
Glory teleport doesn't work in level 30 wild, only at 20.
Ring of wealth can be made so needs removing from the shop for 60m.
Repairing void armour is still ridiculously expensive.
Cancelling skilling tasks is way too expensive. Currently it costs 10k multiplied by the number the task stipulates. For example, I want to cancel a 158 swordfish task and it will cost me 1,580,000. It should be reduced by 10x so that a task like that costs 158k to cancel instead. Personally I have burned through over 100m to get an angler fishing outfit. The point requirements in the skilling shops is great though as it's a real milestone achievement.
Water staff does not count as water runes for spells.
You cannot decant super combat potions. You cannot decant stamina potions.
There are 'ashes' everywhere which randomly appear and do not de-spawn.
There are pets everywhere that do not despawn.
When you recieve a pet drop it drops to the floor instead of;
Automatically following you if you do not have a pet out.
Going into your inventory if you have a pet out already.
Boss contracts - When someone purchases a boss contract the whole server can partake. Say I purchase a contract and recieve a Venenatis task then seconds later some other guy kills it because he is there already. He will get the rewards and the contract will be completed.
Also, the kill jad under 40 seconds task is basically impossible and needs reworking to around 1m 30 (with tbow) but without you're looking at 2 minutes or even longer.
Altars (godwars dungeon and black knight titan) canot be used every 60 seconds. It requires a re-log to use an altar again.
Non-maxed people can wear max capes they got previously form the crystal chest. This just devalues the maxed players. Also, you cannot purchase a max cape yet either (I heard it was in the works).
Performing an action (like chopping a tree or fishing) and then using the ::stuck command will not cancel your actions. So, you can click to fish anglers in the resource arena, then use the ::stuck command and be teleported to edge, and you will continue fishing anglers until your inventory is full.
Agility courses are EXTREMELY buggy. The rope-swing at the wilderness agility course will glitch a player out.
Having max cash in the bank and then attempting to deposit coins from your inventory into the bank will result in those coins dissappearing from the game permanantly.
You can equip a dragon sword as a level 3 account.
Certain skilling capes do not give bonus experience. All of them should.
Vet'ion is not weak to crush damage. Also, he is very weak to mage which is strange as on osrs he is 'immune to magic damage'.
Black Knight Titan will glitch out if there is one person in the room fighting it and one person outside the room (in the altar area). He will aggro the person outside and constantly reset his HP when he cannot reach them. I suggest reducing his aggro range considerably. Corporeal Beast acts similarly too. It will try to attack people outside it's lair in the anti-chamber and will reset HP when it cannot.
Giant Sea Snake's snakeling issue is still a thing.
Mutant tarn's firespot attack can still hit multiple times after it despawns. This happens when you move immediately after the firespots despawn. It's almost like they are still there but invisible for a few milliseconds after they despawn. This results in uneatable 100+ comboes. Frustrating is not the word.
Getting to the Dagannoth Kings' Lair is almost impossible without glitching out on a ladder. I suggest moving the DKs boss teleport to the area before the final ladder into the lair. Basic rings are missing from the game and have been for a while. Also, Spinolyps do far too much damage and the DKs aggro range needs decreasing a lot. It is possible in OSRS to isolate each DK without the other two aggroing.
Cerberus' lava spot attacks do not consistently damage you when you stand on or within 1 tile of them. You only initially recieve damage once.
Cerberus' ghosts come out in a pre-arranged order of RANGE - MAGIC - MELEE always. It should be randomised.
Cerberus' ghosts do not drain prayer when you pray the correct prayer. For example, if I flick pray mage when the magic ghost hits me it should drain my prayer by 30 points (15 with a spectral).
Cerberus is also not very weak to crush attack styles either. META in OSRS is the bludgeon but here in max gear you will not hit over a 30 with it.
Kree'arra and minions do not respawn.
Will add more when I get them.