Essentially a dresden wizard can do anything he wants by act of will. In game we limit this with dice and numbers so we can play it out but in point of fact they are mortal gods.
Wizards are always supposed to be strong. Stronger then vamps and shapeshifters, demons nothing in the game aside from PD have the same "potential".
Nope.
Harry is explictly one of the most powerful and effective wizards in the world, and he spends most of his time getting his ass kicked and talking about how scary other supernatural beings are. He specifically points out, time and time again, that he's an insect compared to someone like the Red King.
And the RPG isn't meant to be a game of wizard supremacy. There's a reason that Evil Hat's suggested PC groups usually have a mix of casters and non-casters; they're supposed to be on the same level as characters.
You can play your game however you want. But the way you portray the books and game rules is just factually wrong.
I see no difference between the two. They do the same thing reduce actual damage.They have different names is all.
Toughness doesn't just reduce stress, it also lengthens your stress track. Armour just reduces stress.
Toughness isn't armour, armour isn't a defence roll boost, and a defence roll boost isn't a block. There are lots of different things in the game that protect you from damage.
Immunity is of course also different from Toughness, since infinity is not a number and it doesn't affect the length of your stress track.
You may think its OP I do not.
You said in the first post, "I think a nice over powered way to boost the defense of wizards ". You specifically used the words "over powered". Have you changed your mind so quickly?
The Dresden rules could be a great way to run a modern day Ars Magica if that is what you're looking to do.
I don't think so, actually. I like Ars Magica quite a bit (I'm GMing an offline game of it), but it and DFRPG are very different games.
Ars Magica is one of the most rules-as-physics-y games you'll ever see. If you like GNS theory, it's "simulationist". The narrative authority that DFRPG gives to its players with Fate Points is totally unlike the way Ars Magica works.
Also, Ars Magica is a really deadly system. The grogs potestas mentions are the usual frontline fighters, and they're intended to be expendable because fighting in Ars Magica is very likely to kill you. DFRPG isn't like that at all.
And one of the central design elements in Ars Magica, the ability to trade time for power, doesn't work at all in DFRPG. The path to power in Ars Magica is to spend in-game years studying and making magical items. The path to power in DFRPG is to have adventures and accept Compels. They're not really compatible.
It's worth keeping in mind, by the way, that Ars Magica isn't as wizard-supremacy-y as it's often made out to be. Hermetic magi are incredibly powerful, but other spellcasters are a lot less impressive. And even magi have weaknesses, like the social penalties of The Gift and the fact that spending all your time on magic tends to leave you lacking life skills.
Plus there are inhuman beings that are substantially stronger than magi, and of course there's God. Who's actually omnipotent and omniscient and so on.