New XP Modifier in Runescape
Think of how bad this would be for the economy. Potion prices would be very high as few people would be making potions, until just after the xp weekend where they would crash. Seconds would also remain rather high, but then shoot way up in the weeks before the bonus xp. Maybe you need more Runescape Gold to level up your character.
Stocking up does not change the sudden influx of pouches and potions that happen after the update is done. Also, many price manipulation clans might see this fairly predictable cycle of xp as a great opportunity, and use some basic plaining ahead to destroy the economy and hurt many players. Our runescape money service will be your best choice if you want to buy service.
Price manipulators had a field day with only a couple weeks of warning, what do you think they could do with several months? Not to mention that Summoning would be a really common 99. Even without bonus xp you can rack up over 1m summoning xp in an hour rather easily, the only hard part is getting charms. Consistently getting 2m xp in same time? It will no longer be a difficult skill.
Mod Marx proposed that they had a set economy in Runescape as well, however, Jagex as well as myself supports the ideas of Mod A. Smith, and prefers there to be free trade. Think of how much worse the game would be if it was a command economy. Supply and demand would have no barrings on the market, and as items entered the game or left the game, prices would never change. Anyways, getting experience in a free market like the grand exchange is rather helpful later on. It is better to learn about stocks in game with virtual coins than in the real world with real money.