Experience gained over level 99 is hunted by players on runescape as well as battlescape, since people aim for 200m experience to earn a higher rank on the highscore and solidifying their rank. Trading off experience over 99 for even a 1m to 100k ratio would be broken with the experience rates for some skills would give you a ridiculously high experience/hour which can be easily farmed to transfer the experience to a slower skill to boost ranks. So that's a definite no since it'd be unfair for players achieving the endgoals that you have mentioned but by actually training the skills.
And for the aspect of creating new items, that's something that reverts back to the way you play the game. Players choose to play ironman to have that "aspect" of getting the items themselves and craft them and work their way to having a maxed account through their grinds, and as far as normal mode goes it's the exact same concept as runescape - with having the choice to grind for the items or buying it off other players.
