It's exciting to see such an incredible rate of advancement; I can't wait to see what transistors at 7nm and less will make possible. I can still remember when these same components were measured in millimeters.
IMO it's a good thing.
The advances are less in your face, but still there.
...but do we really need faster processors? i don't know, but i'd like to have one :)
Any modern processor is much faster than the RAM its programs and data live on, hence the multiple levels of cache inside them. Multi-cores add the complexity of keeping the memory consistent. Multiple threads per core put additional pressure on caches while our OSs assume all processors see a unique and consistent memory image (which requires keeping caches consistent across cores). Our most common software doesn't run on GPUs before extensive changes. Only mobile platforms are exploring asymmetric multiprocessing with a single ISA now.
I don't think we need faster single-thread performance. What I think we need is to adapt our software, which is designed to run on ridiculously fast copies of ancient personal computers, to run on computers that instead of mimicking a successful product of the 80s resemble more what we can do now. We need software that exploits the SIMD units (predicate bits that prevent branches are your friends there), that runs well in multiple cores and OSs that can deal with memory inconsistency between cores (maybe using write-through instructions for shared data and write-back for process-local stuff). We need software that doesn't need complicated instruction reordering or speculative execution.
This is not what Amdahl's law says. Amdahl's law gives you a theoretical maximum speedup given a program with a sequential component and a given number of processors. So as long as that speedup is higher than your faster processor is faster then it does make sense to have multiple slower processors than one faster one.
Sophie Wilson talks about it much better then i could. https://www.youtube.com/watch?v=_9mzmvhwMqw