Well, I am not sure what wish engines in plural are supposed to mean...
As far as ring engine goes... the hard part was to get the ingredients (ring stack in particular, pots could be generated via chaos alchemy (although it was not wide spread/known at the time)). Once you have 19 rings and heap of pots... it is dead simple and boring and you know eliminated any kind of challenge from remaining game. So, IMHO, it was not too funny and based on grind.
I am not sure how numbers were after pots changed from morphing whole stack too rolling per ring, but 'general' motion was what if player has big amount of rings and some water (byproduct of chaos alchemy to generate exchange potions) they could pull it (some wishes probably would go onto replenishing ring stacks). I am not sure it was ever done actually.
Thomas argument I believe was that RoDS engine was not a designed feature... guess he is not of a high opinion on emergent gameplay