I've been playing the server for only around 5 days so far but have come across a lot of things that either is bad in comparison with what other RSPS provide or just simply outdated;
Olm - This is by far the worst Olm I have seen on any server to date and clearly had no care given to it other than the fact that players would've wanted Raids loot and some sort of fight for it;
Now it doesn't need to work 1 to 1 as OSRS as this server has a lot of customs. But at least make sure the mechanics you have actually work. If Solo portals deal 10 damage regardless if you stand on it, there's no shadows during the falling crystals, the phase lasts almost a minute which is far too long in comparison with the rest of the fight. The melee/range/mage special attacks seem to do no damage.
Suggestion; Boost Olm's defense, hp and stats, fix the portals and special attacks, reduce transitional crystal phase time and add shadows to it.
Nex - Can only be done in an instance, makes it unappealing to newer players. Makes the only method worthwhile for ironmen / group ironmen who are working their way up doing event bosses. Which inturn makes so much of the content dead content.
Warmonger - Late game players literally kill it in like 3 seconds. It drops some of the greatest loot in the game and is a World boss - Increase it's stats and make it feel like a world boss.
Wilderness world bosses - Absolutely pointless they need a drop table rework for people to even want to do them. Add some risk/reward to it.
Collection log - I think everyone would love to see a working implemented collection log, yes I know there's one in-game but glancing through it I noticed a lot of it wasn't actually what I have done or where I'm at. Especially those end-game players I'm sure they'd love to see all bosses, pets and content implemented and having something to go.
Wilderness - I've never seen a wilderness so dead and useless. At most there's 3 people in it at any given time, however that number is normally 1.
Skilling - Add a wilderness resource area, or wilderness skilling in general which could give 2X supplies; a way to train skills faster/complete achievements faster but with the risk of dying.
Revenants - More or less pointless, PvP armour degrades and there's no Pkers so it doesn't really have a use; Maybe make PvP armour less obtainable from other sources but make it so it doesn't break, or add more useful loot to the revenants.
Wilderness Bosses - Good for blood money and that's about it, par venantis. Most of them are more or less completely AFKable
Wilderness World Bosses - As previously stated they need a rework, potential for the bosses to have a tb effect when they hit you, Skull when you hit the boss, there's a lot of neat and unique ways you can take it.