Hmmm.... so the exhaust rather than going through the turbine wheel with big holes in between all the slots of the blades of the wheel, it is going to do a 180 DEGREE PLUS U-turn, disrupt the exhaust pulses and to exit from the wastegate. INTERESTING!! Man I guess I need to bone up on my fluid dynamics and go back to class. (End sarcasm)

Now I do realize that not all cylinders are firing at the same time, but I can tell you one cylinder will run with much better volumetric efficiency and could run lean and result in a blown piston, burnt valve, etc. Not only that, but it is going to KILL volumetric efficiency for the other 3 cylinders by having to take that path. At that point you would be better off blocking off that opening with a plate and getting a little bigger turbo with an internal wastegate.

Will it work, yeah probably. Is it a good design, not at all.