DW + Oblivion style spell creation = lol at anyone who isn't playing a DW spell mage.
it would be so broken. 1 hand with 4 spell effects, another hand with 4 other spell effects. basically never have to swap favorites, just be a god.
If spell creation is in, it probably won't allow combining of more than 2 effects, also how would the new hold/tap system work with diff spells in 1 spell?
Implementing an OB style spell creation system does not mean it has to be the exact same system! You can have an OB style system but remove/limit stacking. Or maybe make weakness to magic (or fire, frost, etc) get too expensive, magicka-wise, to try 100% of one let alone all of the weakness spells. Or alter/balance it in other ways. I don't think anyone is saying they should just put OB's system in with no modifications. Just give the players the ability to customize their spells.
Sure, you might be able to have one spell with 4 effects in 1 hand and another spell with 4 other effects in the other, but who said you had to make it so cheap to cast that they can spam them non-stop? The more powerful the effect the greater the cost so if you had weakness fire, magic, frost, and shock in one hand and an abosrb health, fire damage, frost damage, and shock damage in the other it just well might cost 10,000 points of magicka for 100% of each weakness and 30 points of each damage. Or you might actually be able to use it for 400 magicka cost but have only 10% each weakness and 3 points each damage. If the weaknesses don't stack I don't see it as being overpowered (if the magicka cost is right).
And I sure don't want my fire damage spells leveled to my character.
Edit: It wasn't OB's system as a whole that was overpowered, imo, but the ability to stack spells of the same effect just by changing the name.