Leves are finite. The mining and botany also under-reward when you consider you don't get goods to sell. The choice bounces between slightly higher EXP for the time to complete/travel to objectives, or EXP and some gil/personal use. I think the latter far outweighs the former, doubly if you wind up using your leves for crafting instead. Some might twist this into believing craft leves give out too much EXP, but shifting the dynamic from "too much iron ore on the market!" to "too much iron spears on the market!" doesn't really change things if people were forced to craft even more things that don't match demand. I do enough head scratching as is when I go to sell some items and find them below material cost, but I could also blame that on quest rewards doling out gear you can sell. This is perhaps more harmful to crafters than someone getting a gathering profession to 50, say, 2x faster than present. Which is my estimate of the pending change, maybe 1.5x more at lowest.