If Chadwell came from the midwest or the west coast, I'd worry a bit. The biggest hurdle isn't going from G5 to P5, it's recruiting. Chadwell will literally be moving one state over. He's recruiting GA and the South heavily right now, and so has his staff. Walking in with a "GT" on his shirt will open more doors and get the attention of more recruits than "Coastal Carolina" ever would. X's and O's on the field don't change...they're either sound, or they're not.
The other thing is his entire staff won't be coming to GT. It's well known that if Chadwell moves on from Coastal, Willie Korn (curren't Co-OC) will take over for Chadwell at Coastal. Several current staff members will also probably stay behind because it will be their chance to move up. There will be positions Chadwell will have to backfill, and I suspect that's were a coach with P5 experience will come into play.
Honestly, I really hope the new coach comes in and cleans house...and isn't forced to hire a "GT guy". We need new eyes and ears in our program. This is a chance for GT to truly start over. Now if certain people (see: donors) want to put one of "their guys" on the staff because it gives someone beholden to them, then we've lost the plot.