I honestly don't have a good solution but I would like to state the obvious, the whole point of getting geared up is to make your life easier, all scaling is doing is punishing players who have spent time gearing. The money grabs you have in place are your problem, you are trying to balance a game designed around siphoning money from player wallets to be better than most or at max capacity in any given mod.
In all honesty if you would keep your stats and mechanics simple and stop being overly complex your theory of scaling might be easier to translate into reality.
You made enchantments to give players a boost, then designed content around those players that dumped a bankroll on getting max everything to speed run the entire game and average normal people can't participate in. I would think your solution should be to have simple stats that make sense and easily lower those stats but still taking into account that the player who has extremely high stats SHOULD be slightly above the curve for the gear he/she/they have.
I have 14 characters, 10 of which I play to try to keep up, but now days having and average character isn't getting you anywhere, if you are not stat capped max everything go play in old content and do dailies til you vomit and save enough AD to be come max.
The games lacks tanks and clerics, OK so yes this one reason I have a tank and cleric and a paladin (which is pretty much both), i have them pretty close to my main wizard (I have played CW since Mod 2 and frankly is what i enjoy the most but play heal/tank to not only enjoy content in a different capacity but til fill rolls that are needed more than DPS). However the way the game is going I can't keep up several slightly above average characters I feel like I have to pick one and max it out and stay max out forever, of which I have never been a maxed player due to spreading out amongst a wizard, fighter, and healer and sometimes some of the other classes just so i know how to play them.
I agree that you should do something that prevents players from roll stomping and one shoting everything (including bosses). But the scaling being used just feels over the top. Seeing all my hard earned gear that is purple and orange being reduced to the same value of a green piece of gear just makes me laugh and cry at the same time. At least if you are going to scale, make it so that purple gear blue gear has that slight increase over a green equivalent.
I humbly say please stop trying to scale enchants, you put them in the game, if they are so much of an issue remove them entirely and rework your ideas on gear and how players can improve. Sometimes old school mechanics are the best, just based everything on the gear you have not the "extras" you can put in them. Or maybe change enchantments for mods make it so you can't get max stats on every stat but you can choose what items in a gear piece give stats you want to work towards so players can customize play style totally.
I still say keep things simple. And for the love of all that OCD people hold dear, please fix the old artifacts so that they have even numbers again, why on earth did you shave 2 points from two stats and put them in another just so you can see 999 999 1002 and the like instead of a pleasing 1000 1000 1000????