I guess the difference between L4W and LEW/LEB is that now everything is in the PHB.
Do we want everything to be available direct from Daunton, from potions of healing to Holy Avengers?
And, another thought that came to mind when considering the buying and selling of magical items is character to character trading, which would a) have the potential to throw the economy out of whack, and b) be difficult to track, I imagine.
We might consider a gp limit for Daunton. But it's supposed to be a fairly affluent town, so it might be a quite large limit, and therefore not come up for a while. It's more of a flavor thing than anything else. If you want something rare and expensive, you shouldn't necessarily be held back, but perhaps the item's aquisition could be a small quest, rather than a step out to the corner store.
But I do think that player item trading should be nixed outside of adventures. On the isle, all trading must be done through liscensed magical item salesmen who enforce the 1/5 values.