1. Make cutting gems profit a small amount of money, leave dragon hides the way they are, so there's a profitable and a buyable option to level crafting.
2. Remove infinite run, make shortcuts require the required agility level, this just encourages skilling.
3. Add a "Pure Essence Mine" that will require (90)? Mining. Pure Essence will give 2x the amount of XP that Rune Essence gives, although they will take twice to three times as long to mine than Rune Essence, thus making Rune-Crafting a buy-able skill and also making high end mining profitable (although we must ensure that Pure Essence Rune-crafting does NOT make money or Rune Essence will no longer be needed at all). This leaves Rune Essence as a profitable buy slower way to train Rune-crafting.
4. Increase the prices that raw resources (Ores, Logs, Fish) sell to the General Store, This increases their general value, and that will increase market value, meaning skills like Fire-making, Fletching, Cooking, Smithing and Herblore become buyable between players, also making a more competitive Highscores.
5. Slow the process of Cooking Raw Fish, you basically cook a entire inventory instantly.
6. Unsure about this one since no one really knows how much gold there is in the game, but Thieving might be overpowered, roughly calculated, you can make 60-70m from getting 200m Thieving. Might be fine, might need a slight nerf.
7. Remove Abyssal Whips from the PvM store, high end slayer and bossing should be the best money maker in the game. It's going to be faster to just camp rock crabs until you get 800 points rather than getting 85 slayer and camping for a whip drop.
More Coming soon. this was result of a quick brainstorm.