Let me start this by saying I think the ring of wealth is a really fun item. When I find one in any of my runs, I immediately get excited. That is, for all of 5 minutes before I realise I feel obligated to play a RoW run, sinking at least a dozen hours of mindless grinding into becoming God. In short, RoW is far too powerful, and so ruins both the fun and challenge of the game. Now I know what you're thinking :
If you don't like the item then simply don't use it, why ruin everyone else's fun?
And that makes sense initially until you realise that finding a RoW in say a crystal chest is just a complete let down if you don't want to use it. Not to mention the fact that I KNOW that I'm not the only one who feels dread when faced with an early RoW. This is why the solution of disabling it in runs where challenges are active makes the most sense to me. The overwhelming odds are that people who play the game to simply make fun powerful builds play without challenges, and people who play the game for the expertly crafted challenge it poses play with challenges enabled. This has the added bonus of making the super hard badges like 1mill score actualy hard rather than the majority of people feeling the need to cheese it with the RoW. As for the problem of this being an unituitive change, a simple pop-up the first time players select challenges explaining their general idea and this change should suffice. A rework of its mechanics could also be a viable solution, shifting it to focus more on rare loot drops over the boring and grind inducing drop rate multiplier.
Another reason that RoW is a problem, though I'll admit perhaps one only 00-evan will have to consider, is that it's very limiting of design space. As an example for this, I recently tried designing some new sub-classes for the game, just for fun. One such sub-class revolved around their powers magnitude being tied to either alchemical energy or unique alchemical crafts. Clearly, gaining even a slightly upgraded RoW with this sub-class would be fundamentally overpowered. It's not just this example either, it's very easy to imagine a world where a cool new feature being considered added to the game would be unbalanceable around the RoW.
At the end of the day, this is all just my opinion and a suggestion, please contribute with your own opinions on the matter, or just shout at me about why I'm wrong :p. As the Civ IV devs famously said: "Given the opportunity, players will optimise the fun out of a game."
I disagree that ring of wealth is as powerful as you are making it out to be. Also, it seems like half of your motivation to make this change is because you can't resist the temptation of a RoW run when presented with the opportunity.
Every time I see a person who grinded for hours and hours to get hundreds of every type of consumable, I see a run that probably would have been easier to win with that ring of wealth left at +1 and the SoUs invested into more straightforward strategies.
My highest successful RoW run was 7 challenges, and I HATED that run - it took forever, and I had to play carefully for so much longer than a conventional run. The others times I tried a RoW run at 6+ challenges, I died before I could reap the benefits of the ring of wealth or made a mistake while grinding and died.
Like someone else said here, I would take a ring of haste over wealth any day. I advise most of the people on this sub that ring of wealth is a trap - leave it at +0 or +1 like you would with most other rings.