Sure, a 128 bit quad channel bus is effectively a 512 bit bus. AMD and Nvidia have used 512 bit buses in the past, however they both have moved away from those due to high cost and high power consumption. If Bitmain's ASIC really does have a separate 512 bit bus for each core (so 18x 512 bit bus in total), then 200+ MH/s is possible. However, in that case the retail cost and the power consumption will be pretty high. I'm sure they wouldn't release anything that's worse than a comparable GPU rig but most likely it's not going to drive GPU rigs out of the market either.