So you want to do the same quests over and over, but not the same leves over and over? Also, as mentioned above, you get 6 leve allowances per day, not 3. You get 3 every 12 hours.

Also, your view on leveling is horribly, horribly skewed, not to mention you lumping all DPS, both melee and ranged, into one clump. Melee DPS have significantly faster queues than ranged DPS, and even on a ranged DPS if you're waiting 45 minutes for a dungeon you're doing it wrong.

Levequests aren't the only way to get venture coins - in fact, they're probably one of the slowest. Hunts, treasure maps, GC seals, beastman dailies - all of them net you ventures.

Besides, there is already enough incentive to play more than one class - for example, getting Swiftcast for ALL casting classes/jobs, or getting Provoke as a Warrior, both of which are by this point effectively mandatory in endgame.

In short, it is an overreaction.