Let me start by saying I really agree with your goals!
I really think the presentation would improve by giving
an example thou'.
Especially the "ei" bits come across as heavily theoretical. A picture tells more than a thousand words!
Thanks, I'll think one up in the next few days. I blame laziness for avoiding an example in the first version
.
I intentionally had some "heavily" theoretical stuff because it's important to me to have a reasonably firm assurance that the new system is indeed equivalent to the old system. You can skip it; it should be fairly clear that if items tend to be no more than 60% of their full worth that raising treasure by one level (i.e. 38% value) is pretty safe. But if you want to take even later reselling into account and put all the bits together, it's there.
That said, I'm not convinced the 20% sales rate is at fault here. What are you supposed to do with the extra money?
You say yourself the extra gold is all but irrelevant when it comes to buying useful stuff. (Even if you got 100% when selling stuff, as per your example).
Theoretically, nothing you can buy will compare to the things that "drop". Not as long as you don't change the curve, that is how every five levels also fivefold the price.
If you sell
old stuff, the buy/sell ratio is not that important due to the exponential price rise over levels. After all, even at 100% stuff that's five levels behind is just 20% of a new item.
However, with random loot, people will need to sell new stuff regularly - stuff that just dropped. Here, the buy/sell ratio matters a lot.
Sure, in practice, there are quite a few items of your level or lower that are desirable. But they are almost all mistakes, pure and simple. Anytime your epic character picks up a bunch of heroic stuff because it is useful, a mistake has (almost by definition) occurred.
Well, that's dependent on specific items. I can well imagine low level items remaining useful, but generally just as an extra option, not as an overall power increase. In any case, that's not too relevant to the wealth system; after all the plain DMG system makes it easy for PCs to acquire low level items too by including a very heft gold amount each level. In any case, this is outside of the scope of this wealth system, for sure ;-).
So why change the 20% sales percentage? Why not change the exponential price hike? (If your goal is to allow players to use money to custom-buy what they don't get through drops).
The exponential price hike is good because it makes it very very hard to sneak past fundamental assumptions by saving smartly or by a party pooling their money. It's a very solid fundamental building block that gives solidity: by having the price rise by a factor 5 every five levels, even a factor 2 or 3 imbalance in wealth just means a few levels advantage in wealth - not even a single +1 on a weapon. That's robust; I don't want to get rid of the exponential scaling for that reason.
In fact, why not keep the system as-is and simply
fivefold the amount of random loot in the game?
Edit: I meant "why not increase the amount of loot fivefold when you make it random?"
Your math should quickly tell you that this will amount to a very small increase in player power, because 1) the junk loot remains worthless and 5xworthless=worthless, 2) there's a limited number of slots anyway, very soon any increase will be incremental at best.
And of course 3) by increasing the rate of loot by five, the importance of getting something useful just dropped by 4/5 - essentially you get five tickets to the lottery each level instead of just one*
*) one magic item for each PC except one, who gets gold instead. Except in all those groups where gold is always split equally.
I guess I'm using your own argument that the system is inherently fail-safe (as long as you keep the x5/5 levels price hike) to argue your math is probably way too involved and detailed than necessary...
My reasoning behind this choice is in the post titled "
Why the 20% sale price needs to go". In short; you
can simply grant 5 times the items instead.
But that's more complicated in practice because, well, it involves altering the # of parcels, just adding one level is really easy by comparison - you can run premade adventures with almost no change, just raise each item by one level.
Secondly, you'll have more variance if you simply grant 5x the items. If the sale price is half and you just raise an item by one level, then a lucky PC just "gained" 1 level on one item. If you grant 5x the items, it's not unlikely to have a PC that got lucky and gets
several appropriate items; after all you're distributing 20-25 items each level. That might disrupt intra-party balance somewhat. No, this probably won't affect balance in the long run, but balance in the short run is important too.
Handing out that many items is also just more work for the DM; more items to choose, more items to make fit the flavor, etc. Also, I like
sometimes handing out an appropriate item - and if the number of items isn't radically different, that's OK; if the number rises dramatically, you need to be careful to not imbalance the game (not to mention the fact that magic items become a lot less dramatic when you find half a dozen each session).
Finally, as a detail I don't like the (small) incentive the current system has whereby PC's try to pick items that remain useful indefinitely. If the sale price is a little higher, it's a little less important to pick out items that will be useful forever; switching is cheaper. This is a small step towards balancing hard-core gamers versus the more relaxed sort that didn't preplan every character choice X levels in advance.
To cut a long excuse short: you're right, you can definitely just increase the number of items by a factor of (slightly less than) 5 and make no further changes without dramatically altering balance. On the other hand, that solution does have a number of small issues which is why I prefer the raise-by-one-level and sell-for-half approach. It's not like that's much more complicated - it's actually simpler in play, even, I hope.
