Disagree. They’ll have to learn a deeper playbook, understand defenses, learn audibles, recognize blitzes, read coverages. QB is a lot more than “needing someone to complete passes”, which isn’t a simple task in itself.
Mate the CPJ playbook isn't less complex than the menu playbooks most teams use. The difference is the way its taught.
As for pass trees. Sicne CPJ's book is mostly PA and footwork to create throwign lanes to option routes (aka the hardest route to teach nfl recievers and why the patriots offense is so potent). The blocking schemes are also about to get really damn simple.
Lets take a flex pass
Spread 789 (simple play call right? so who does what? oh right you actually have to remember the series and your assignment based on position)
I don't know the actual call cpj used but in the version of the offense i ran this was a backside post frontside option favoring go (9) Backside A goes in twirl motion and runs a flare while the B back fills for a pulling guard setting for a boot seal on the end to create a running escape lane and the frontside A back runs a drag to pull the linebackers out of a slant lane should the corner bail and the receiver read slant. The QB has to perform a counter step to make the play look like either rocket or speed to the twirl a-back then sink to depth and read the 1 receiver or corner to know to throw the slant or go. If neither are there his next read is the rush lane to get 5 if that's stopped its the A-aback drag or the backside post (scramble release counter to estimated fire pressure which took away the rush lane)
In the offense we are likely going to.
Gun Ace Slider Xray Cross Yankee Z Motion
This is a similar play however we no longer have an option route. Also the receivers don't have to remember routes based on a number system. They just listen for key words. In this case assuming that recievers have a default route based on call order and whether or not they are actually in the play call. So for this one you have a gun ace set with a slot (11) the tightend blocks to flat escape, the X receiver is running a deep crossing route. the Y receiver is running a GO and the Z receiver is motioning from base to to the other side of the formation and likely running a drag or slant to clear for the flat. The Slider call tells the line they are sliding right. Much less to remember. The Qb's reads are in order of receiver call. He is suppose to read the Cross, then the go, then the Z and finally his safety is the tight end in the flat. He is doing this not off play action (or maybe off a built in play action with the running back but because they are in gun that means his eyes still read the safety. This is system that is used by the majority of spread teams. The reason being the individual assignments are easy to translate to play cards and run no huddle without communication issues. This may not even have a verbal call in such a system.
In reality the CPJ playbook is deeper with more variation on a smaller subset of plays. The normal Spread playbook is very shallow to facilitate speed. Variation is done with a variety of single use plays based off a core package ( most of them being zone read or inside zone)