The proof is in the results. If the Cell was all that it would be used in considerably more applications than it currently is. In single threaded performance and efficiency the X86 Intel CPU is king, in price/performance applications ARM is the one to beat and for high performance computing there isn't much out there which can hold a candle to GPGPU/Xenon Phi architectures.
The majority of the major optimisations developers have made are for graphics processing which is irrelevant if you attach a very strong GCN AMD GPU to the console. Once you've done that then you're going to throw away the majority of your legacy code as it simply isn't needed anymore.
Tease.







