Well... As much fun as I had when I discovered it, I quickly stopped using it because it didn't see the point really. the only thing worth duplicating were soul gems.
Sarcasm aside, a bug is a bug and bugs need to be patched.
Weakness to Magicka on self giving you weaknesses to positive magicka effects was an unintended part of the game by the developers, and in my opinion it made magic beautiful. Why? Because you could heighten your focus on your own magical ability in order to unlock the true potential of your mage and enhance your own potential. That came at the expense of enhancing an enemy magical effect. Now, what it did was create two magical spells. It created one that you used in order to be able lower the resistance to magic of an enemy, and it created a spell in order to enhance your own focus on your spells at the expense of your own resistance to magicka.
So what did Bethesda do? Rather than build on this unintended feature, they patched it.
Now it could be that you could create a chain of magical spells in order to get fortify health 2000 points using that effect. But the effect itself is not named correctly post-patch. . Post patch it should be called "weakness to magicka - hostile magical effects because otherwise it creates a game imbalance."
The fact is, sometimes bugs actually create a game feature that enhances the enjoyment of the game. In that case, dup'ing 10,000 watermelons caused cool physics effects, in my case, it created a spell effect that my mage could use once at the beginning of a fight in order to focus his mind and cast more effective spells, at the expense of spending longer being unable to cast spells if the mages he was fighting used a silence spell, or he would get annihilated to a worse degree than normal if the Orc beserking towards him had an enchanted war hammer. Sure you can exploit the glitch, but in Skyrim you'll be able to exploit the fact that killing lots of dragons will make your dragonshouts incredibly powerful. Personally, I don't see the difference. If the character fortifies health by up to 20,000 points and thus doesn't experience any challenge throughout the game, more fool him, he's only ruining his own experience of the game, and it won't effect my experience in any way. By the same token, you could obtain gold in Oblivion by looting the chests in *imp gall cave repetitively without killing any imps (or for that matter, the boss at the end), by just running past them all with zero encumbrance to begin with (or while only carrying the feather pants available to any character from level 1) - you're still obtaining results without a great deal of challenge, particularly at any level above level 10. But at the end of the day, is it really affecting the game experience of anyone else but you?
*I'm fairly sure that imp gall cave is the cave that only has imps in it and has some outstanding loot, but I could be wrong.