Need advice, horrible ride after accident...

I've got a 2008 prerunner SR5 4cyl Regular cab. Was in a accident in Feb, was a rear end collision where they replaced the drivers side rear leaf spring because it was bent and the collision also blew out the driver side rear tire. The truck has 94k miles on it with the original leaf spring still on the passenger side. Got the truck back this week and it rides like crap. When doing 65-70 mph, there is a horrible vibration that you can feel in your seat and floor board. The way I can best describe it is that it is not stable in the rear and feels like the back end is not staying on the road. It is a horrible feeling, like I don't trust the truck anymore. One guy who I took on a test drive called it "roadwalking" if that means anything to you.
Took it back to the shop today and they called back saying that my Front left tire has flat spots causing this vibration (General Grabbers AT2 - LT265/75R-16). They are the exact same tires I had before the accident in the front and there was no vibration before the accident.
My question, could them only replacing one leaf spring be the cause of this new vibration? Also, if they replaced the new one with a different one (4 leaf versus 3 leaf), could that cause this? I've attached pics right after the accident. Thanks in advance for any opinions...

 

Having 4 leafs on the driver side and 3 leafs on the passenger side sounds dangerous IMO. Did this go through insurance? If so, call them right away, like now.

 

I'm no expert, but it seems like an impact hard enough to bend your leaf pack like that might just be enough to bend your axle/axle housing which might cause the vibration your describing. Or possibly messed up the bearing? Just a thought. Best of luck.

 

I would guess with different leafs, the driver's side is quite a bit higher than the passenger side? Maybe measure hub to fender on both sides and see if they are the same. Also, are you sure there is no frame damage? It doesn't look like it was too hard of a hit so it probably isn't likely but snapping a pic where the cab meets the bed from the side would be helpful.