Ok, knowing who this is coming from...
I don't think its that bad at all.
The Kappa cars have lightly welded tabs for the A arms of the suspension to attach to. All the kappas with signficant front end hits have had the A arms ripped off the frame mounts. It helps dissapate energy from the hit. So the fact the rear wheel is askew is normal for Kappa in my opinion.
So you need a rear quarter panel. The service manual shows how a shop should replace it. they drill out the spot welds and then heat the glue with a heat gun and it comes apart. Reweld the Arm mounts, new rear bumper skin, align everything and you're good to go. Hell the trunk didn't even seem to be affected, and frame - is probably still intact except for the pesky A arm mounts. Cost will not be cheap with all the parts and labor though.
I doubt its a write off.
'12 Kia Optima SX GDI turbo
'07 Custom Blue RL conversion, Auto (project - not running yet but working on it)
'06 Honda Odyessy EX-L minivan