A lot of this is wrong.
The whole point of the power levels in the game is to put characters on a level in terms of power. A Chest Deep mortal is not supposed to be weaker than a Chest Deep Wizard. But your average mortal is well below Feet In The Water while your average wizard is probably Submerged.
Even at the same refresh level, wizards are, one on one, more powerful and dangerous than a pure mortal when optimized for combat. The wizard is going to be tossing out Weapon:5 spells at rolls of 5--without taking into account specializations and focus items--and will more likely than not have enchanted armor of significant strength. The Pure Mortal, unless he's carrying a bazooka, isn't going to be doing more than Weapon:3 damage, and his armor, if he has any, is going to be limited in scope of what it can block. Kevlar isn't going to stop a fireball.
Also WCVs and werewolves will get killed if they try to fight optimized mortal combatants of the same power level.
Seriously, mortals are pretty kickass. And WCVs and werewolves are distinctly suboptimal. If you were right about the intentions of the game designers (and I'm pretty sure you're not) then they failed really hard.
All other stats being equal, WCVs and Werewolves who have speed and strength powers are going to beat a mortal combatant, stat for stat.
PS: Why does Harry's identity as a wizard make the game Wizard-centric? He's also really tall, but nobody claims that the game is about tall people.
I would say that the books having several sections dealing exclusively with spellcasting, how to build a spellcaster, and the consequences of spellcasting (the section on the Laws) would make a good argument that the game is kind of centered around wizards. As the game itself notes, "It's not called The Borden Files."
PPS: Even at 30 Refresh, you might well lack basic combat competence. There are other things to invest in. And Wizards, for all their power, tend to be pretty fragile. So having mooks kill the Merlin would be quite reasonable if not for the Merlin being smart enough to avoid those situations.
You could, but, uh, that'd be kind of a screwy way to play. Though I'd say if you're a wizard with most of 30 refresh spent, a lot of that would've likely gone to Refinement, which means your martial abilities are at least decent unless you focused them all on Thaumaturgy, which, again, would be kind of an odd way to play a PC.
And I totally agree, having mooks kill a powerful wizard is possible and reasonable--they just have to catch him unprepared. A wizard can certainly toss up a 9-shift shield to keep goons out--but he has to have a turn first.
PPPS: Using the Laws to balance Evocation is a bad idea.
But...they are a balance against magic. That's exactly what they are. The Laws of Magic are explicitly there to protect pure mortals against wizards. How many times in the books has Harry faced some mortal goons and either gotten his ass kicked, had to run away, or had to brawl it out, because they're mortal and he can't risk killing them with an errant spell? In Storm Front, a mortal goon nicks some of his hair--Harry immediately realizes this is a life and death scenario, and if the goon gets away, some wizard is going to kill him. So Harry...tackles him. Because he can't risk hitting him with a spell and killing him. When Harry's attacked by three goons in Heorot, he has to fight them hand to hand instead of just laying them out with a spell for the same reasons.
Harry makes a deliberate effort over several books to better defend himself hand-to-hand because he can't just toss magic at the human goons he keeps going up against. In game terms, that's a wizard focusing on boosting his Fists and Athletics scores instead of his Conviction and Discipline specifically because of the laws of magic.
In short, if a magical practitioner isn't worried, concerned, or thinking about the Laws of Magic in some way when he casts a spell to attack a mortal, there's something wrong. That makes them a balancing factor meant to limit the number of situations in which "hit it with a Weapon:8 spell" is useful.
Given how nobody agrees on how the Laws even work, and given that the Laws only apply to a fraction of the game's characters, and given that breaking them is more or less instantly fatal, they make a crappy balancing factor even if you deny the badness of narrative balance.
Molly and Harry seem to have broken laws without it being "instantly fatal." And it's not meant to be a full balance to bring Wizards down against everything. As I said before, I believe this is a setting where Wizards are
supposed to be badass when they can let loose. Going against mortals is supposed to be one of the times Wizards simply cannot afford to let loose. Letting a wizard blast--without concern or consequence--a room full of mortal goons into submission goes against the spirit and rules of the setting.
PPPPS: Wizards aren't actually as supremely badass as people here seem to think. They have a lot of firepower, but not the most. Their out-of-combat abilities are strong, but very narrow. And their basic abilities cost so much that they tend to lack other abilities. Like basic not-getting-killed skills.
Yeah, that's what I was getting at with my math example. Wizards can be really damn badass, but generally only in one, maybe two areas until they get to the really high power levels. The problem I keep seeing is people seem to assume if a wizard can toss out a 12-shift shield spell, they can cast other spells of similar power too.