It would be enough just to reduce the number of rings that can be dipped into a potion at once, for instance to 9 (why is it 19 to begin with?), or the number of potions gained from the wish, simply to adjust the odds.

It's 19 because that's how the formula is set up -- you can dip 19 stones worth of stuff, rounded down (with a special case for missiles). Capping this at ~10ish for rings (leaving the formula the same for everything else; could just have a check after the formula to max out at 10 or whatever) would be a fine and easy fix.

A possible solution that I posted earlier:

How about if dipping rings into potions of exchange caused EACH ring to be exchanged, rather than ALL of them? In other words, you might have a higher chance of getting one RoDS from a dip, but you wouldn't be able to re-dip all of them.

Alternatively, make the chance of a potion of exchange causing a ring to become a RoDS lower than the chance for other types of ring.

My personal preference is to make it that PoEX can only dip 1 item at a time (the same mechanic as potions of raw chaos).

I don't think this is a bug that should be fixed, and personally I like wish engines ;) Although I can see why people are concerned about nerfing this, as a single successful dip can result in 19 free wishes which severely decreases the difficulty of some parts of the game.

Each individual item now will be exhanged.

I take this to mean that you can still dip 19 rings in one potion of exchange, but each one gets exchanged individually? If that is what has been changed, it does not stop ring wish engines from working. On average, you would get the same number of new wishes per potion of exchange. To be honest, it just makes the engine easier to start and maintain once you have enough rings because there is very little risk of getting no new wishes this way.

Sorry if I misunderstand.

Edit: ok, I stand corrected.. someone pointed out to me you would need a really large amount of rings (some 400), which makes it harder for sure.

I agree. I think JellySlayer's fix would be much better.

The main difference is that you don't get a stack of rings to re-dip. If you dip 19 brass rings, you might get lucky and get one RoDS. More generally, you're likely to get, say, 2 rings of acid resistance, a ring of ice, three rings of fire resistance, two rings of the fish, etc. Now, unless you have heaps of rings to begin with, the chances of having a reasonable stack for re-dipping is much lower. And then, to set up a full wish engine, you'd need a way to effectively produce somewhere in the vicinity of 19 RoDSes by the various dips during a set.

Think of it this way - making it exchange each ring separately makes it harder to set up a wish engine, but easier to get a single wish - which is precisely what the main aim is with all of this.

That said, supposedly there's a 4% chance that a ring being exchanged becomes a RoDS if done at the appropriate danger level. If that's true, then there's a better than 50% chance that dipping 19 rings will produce at least one RoDS. That may be a little too high... although it's not going to be as easy to obtain 19 rings of the same type as it used to be, now that pickpocketing doesn't work on summoned/bred creatures (and I assume gremlins produced by water multiplication, etc).

The Wish Engine doesn't need to be made completely impossible, just highly impractical (in 1.1.1, it was merely impractical, mostly just requiring time to set up).

I like the fix, because not only it makes the wish engine more difficult, but it also makes a "casual" use of potions of exchange much more interesting. Dip 19 brass rings and get 19 new different rings? Hell yeah.

The new solution sounds good to me. You can still ring dip and have a shot at getting that RoDS to save Kelly you want so much, while the potential outcome of a whopping 19 wishes is eliminated. And if you do the dipping on a high-DL area, you could get other interesting rings too, e.g. elemental mastery.

It seems the only way to get infinite wishes now is being an archmage! :D

Actually becoming an ArchMage will be quite an achievement now.
You pretty much had to set up a RoDS wish engine in the first place and make it running at 300-400 RoDS to consider the path to archmage.
Now without RoDS dipping abuse, archmage will be sooo much more difficult.

You'd have to get 19 stacks of 19 rings to get it to work, wow