I have the first year (2011) of the 3.5L job ticket 2 (meaning I got the first round of production updates in the first year of production)
2012 got rid of two annoying problems with the 3.5L The too weak of a timing chain and the external air compressor mounted behind the left front headlight used for boost for the master cylinder that internally rusts and dies and costs $600 and that Ford is quietly offering a free extended warranty on until 150,000 miles.
I also taught the internet to drill a 1/16" weep hole at the bottom of the intercooler (something Ford cannot do because of emissions) and not install all the BS shields to keep the engine from ingesting a slug of water, hydro-locking and throwing a rod out of the block.
The original 3.5 gasket at the fuel pump can fail, and like a bunch of diesels, dump fuel straight into the crack case until it grenades.
All of the direct injection engines suffer problems with carbon building up on the backside of the intake valves and this is a PETA problem because if a top end engine cleaner is sent through the engines, enough to clean that carbon, it'll overheat the turbo seals and eff the turbos up. My solution was to put on a giant catch can and dump all of the recycling emission garbage into that catch can. Works great until winter when the catch can freezes and it is hard to drain out.
The cams and fasers can screw up to the point where I, as a mechanic will send it over to Ford to do.
The injectors are retarded tough to replace and you may not know if they aren't seated right until you fire the engine back up. So this too is a "Good-luck, Buddy" job at the ford shop unless you've got nothing to do and all day to do it.
The redesigned engine fixed the all-too-narrow injector install problem. It fixed the fuel pump gasket problem. And it fixed the valve carbon problem by adding an injector in the intake plenum to allow fuel to wash the carbon off of the intake valves.
Other than that, these are good engines.
FWIW, Ford typically recycles 70% of their existing parts content from design change to design change.