ive only ran a couple of games, but both of them had fairly wide arcs. And refresh has always been a pretty good balancer as far as i've run into.
There are certain times where certain people shined, and wizards can often be powerful, they have abit of an edge which comes from the drawback of fallout/backlash and finite supply. They have alot of power to dish out but the tank runs empty pretty quick, meanwhile your emissary of power (who isnt using all of his refresh it would seem) gets to throw his fist 5 + inhuman strength around, dozens of times if need be.
Also with that in mind, perhaps your sorceror, Emissary and Cop character may wanna be passing tags back and forth between them to help level the playing field, as that would make a difference.
I also dunno what Truth sight is or how it works, but if the character is that concerned about his combat viability he may find himself more suitable as a pure mortal for the extra 2 refresh and stacking combat stunts. TBH one of the most dangerous characters I had was a well-twinked, stunt-stacked prepared pure mortal. Granted not usually what I go for in my games, but he was actually more of a problem for me to balance than the wizards with the rest of them.
Id have to see full character sheets to say alot more on the subject, and if they are all looking for pure combat viability, we may be able to help bump them up abit. xD
Also its a matter of your setup: If these were just random thugs that'd be one thing and they'd prolly get wiped up by the wizard, but three denarians. Unless they were fighting three denarians that all happened to be magog, you are looking at some people with LOTS of power, but also scary clever and smart. Before attacking this group, they'd have done their research, they'd have pegged the wizard as the biggest threat from the get go, and from their theyd either purposefully force him to expend his power by staying on the defensive, or they'd use some magic of their own to lock him down. If they needed to attack, they'd coordinate and make him their number 1 target (hit him hard and fast, take down the heavy guns and mop up the rest.)
As with all things in fate, the narrative is a big factor.