I find it funny that the term 3-4 or 4-3 is still used as if its an either or situation.
Most defenses in the league, run a transitional D with multiple sets, all it really means is the deeper you are the more flexibility your defense has.
The players like Neal, Kazee, Parsons, Gallimore, etc..etc... allow for position flexible options esp with Neal and Parsons early.
When you have flexibility where you can move Neal from LB to safety and Parsons from MLB to pass rushing DE before snap than you have the ability
to give a QB an entire different look.
The biggest issue early will be getting players comfortable with the shift changes on the fly, but why I feel Neal and Kazee where so very important, they were already fluid with Quinns scheme,
and why Kazee seemed to just move so well in early observations during OTAs,, sure he is healthy, but the fluidity was also very indicative of what Quinn wanted,, players that already know the pre snap
adjustments, and transitional movements esp with the DBs.