I'm seeing this as well, for all Devices attached to the machine.
My operating assumption for me is that they forgot to include 32-bit resources in the 11.4 distribution, but it seems that's far from common in the errors others are seeing.
Other symptoms include the pervasive "Can't load AppleUSBEthernetHost.kext" error (after deleting and reinstalling from iTunes 10.4 pkg) it still won't load because it lacks 32-bit resources,
% sudo kextutil AppleUSBEthernetHost.kext
Warnings:
Executable does not contain code for architecture:
i386
Can't load /System/Library/Extensions/AppleUSBEthernetHost.kext - no code for running kernel's architecture.
Failed to load /System/Library/Extensions/AppleUSBEthernetHost.kext - (libkern/kext) requested architecture/executable not found.
I'm also experiencing the console spam from iTunes Helper crashing and respawning repeatedly and filling up the system.log - apparently in "AirTrafficHost/ath" code.
In any case, the net result is that, while devices (ranging from the iPhone 3GS and 4S to the iPhone 5s and iPad Retina Mini, both with and without "Sync over wifi" checked) do show up in iTunes 11.4, they show as mostly containing "Other" resource types with disabled "Sync" buttons and manual backup buttons that return quickly without initiating a Backup. It's possible iTunes is reporting something in the system log when this fails, but since the logs are overwhelmed with iTunes Helper errors, it's impossible to tell without a lot of sifting.
I'm near the very bottom end of Macs which are within the iTunes system requirements (10.6.8, Intel Core Processor): Mac Mini w/Intel Core Duo (32-bit) + 2GiB RAM, plenty of disk.