I would highlight the PzC tactic of stacking a number of units in a hex to use their combined firepower to disrupt a defender is the biggest vice PzC players can carry over into FWWC, in PzC there is no real negative to stacking multiple units in a hex but in FWWC you will suffer huge amounts of casualties from defensive fire and artillery (see explanation in my article).
In FWWC you will need to use field gun and MG units to wear a unit down using ranged fire before you think about an assault so attacking does require more planning/patience than PzC which I think is the greatest hurdle to PzC players enjoying FWWC, if you are a
very impatient person then you might find FWWC titles a tad frustrating.
So the two series look very similar but the devil is in the detail, if you are prepared to slightly recalibrate your playing styles then playing the FWWC series will be as much fun as PzC.