It's clear to me that spirits are broken. Any magician can summon in an instant a Force 5 magical bulldozer that's nearly impossible to kill via mundane means, and is probably going to beat your magician in initiative and snap her in half before she gets to do anything about it.

It is still a Complex Action (quite possibly with a bit of Drain for starting chanacters), and a group of mundanes can deal with a Force 5 spirit. Especially if they have FA weapons loaded with Ex-ex/APDS or a Grenade Launcher loaded with HE and have room to coordinate and manuvuer to minimize friendly fire if the spirit closes for melee. Of course the first person per IP leaving melee range from the spirit is still going to take a smack upside the head, but Force 5 melee is just another kung-fu expert.

EDIT: You might lose someone though if the spirit engulfs and friendly fire is the only way. Although arguably the engulf victim should be mostly protected up until the disrupting blow.

It's Force 6 where things really starts to get hairy because you quickly start losing mundane ways to break through the hardened armor. And yes, at that point sanity leaves the building and hops a plane out of town.

Which only creates unmaneagle paranoia in the players - fearing spirits, they won't even go to the bathroom without their Ares Alpha with APDS.

I've said this before - in the canon, spirits are the tactical issue. You have to structure all your tactics around the goal of defeating enemy spirits, or you're f!cked. And if you don't have a conjurer on the team, you're a big fat dope. You're bringing a knife to a gunfight.