pawsplay said:
Chicken farms, indeed. Who says that vengeful DMing is a lost art?
I have a hard time thinking of logic, economics, and versimillitude as "loopholes."
Only an utter moron would refuse to allow the PCs a hard won victory over great obstacles.
IMO, it is the DMs duty to maintain game balance. If a player came up to you and asked to replace their fighter's daily power with:
Heroic Fighter Power X [Monthly, Reliable]
Hit: 99[W]
would you allow it? Would you allow it if he gave you logical reasons for it, such as a quest he had to go on to find the one master of this special @sswhoopin technique? If he pointed out to you that since it is only once every 33 days, it should be 33 times as powerful as a fighter daily? If he wrote a fifty page short story justifying why his character should have this power?
I wouldn't. There are some things that imbalance the game. That power would be one of them. Allowing players to regularly sell their magic items for 100% value and buy items that are X levels above what they're supposed to have is another.
Granted, if you enter into a gentlemen's agreement (as someone in this thread suggested earlier) that the money will be spent on items that don't increase the PCs' power, like a castle, I don't see a problem with it. If you enter into an agreement whereby the players are trading equivalent magic items with the trader, that'd be balanced too (it wouldn't make sense from the point of versimilitude- how the heck does this trader make money if all he ever does is trade items of level X for items of level X- but it should be balanced).
But if your players are able to sell off all of their magic gear at level 10 (or even 15) to buy even just one level 30 uber sword of god-slaying, it suggests that the DM may have made a mistake. The party will be lob-sided and actually more prone to dying because of this (since they've pawned all their defensive gear), while at the same time the god-slayer wielding fighter will blenderize everything in sight. That's not a desirable outcome for anyone, as far as I can tell.
It isn't the DM's job to punish the players, but just like a child trying to stick their finger into an electrical socket because they're curious, sometimes players can be very short-sighted. The uber level 30 god-slaying sword (at level 10) that looks like fun today, may well ruin the campaign tomorrow. That's when the DM, like a responsible parent, has to respond with a firm NO. If your players don't need this kind of regulation, fantastic! Some, however, do.