2014 F350 Lariat DRW 4x4 8' bed. Had to downgrade from the Platinum. :-(
If the two truck are comparable in features, I would think you did alright in your trade. Jumping from SRW to DRW is $1200 MSRP difference alone, for $2K more, on a truck that probably lost 10% the minute you took possession is very good.
The Platinum is a nice package, but with the Lariat the 3 things you lost that first come to mind are the shiny tailgate cover, the Platinum stitched seats and the heated steering wheel. No great loss in those 3 upgrades.
You will be better off with this change then buying oversize tires and wheels and adding air bags just to be able to tow with some margin of comfort.
But that all said, you may be adding air bags anyway
At least now you will be within your truck's ratings instead of way over. It is very easy to get a 18K GVW 3 axle toy hauler up that 18K number and not very hard to easily surpass it.
The truck is quite capable of handling the weight, but all the Fords drop a bit until they hit the overload pads. Just enough to make the headlights a bit high on DRW's.
DRW Fords have a 2" spacer block between the axle and springs, SRW's have a 4" block so the rear end drop is not as noticeable. For this trade off though you get a lower rear end height to start with, which can be a comfort thing as well.
Good luck, I think you will be pleased with the performance. After 54K and 3.5 years with my first Ford I still am pleased. They are not perfect, but all it needs it a real exhaust brake.