A runtime deprecation warning was not emitted in 3.3 because two alternatives, time.process_time() and time.perf_counter(), were not available before 3.3. It would be hard to write a warning-free code that supports 3.3 and earlier versions at the same time. But now 3.2 is virtually out of use and I think we can start emitting a deprecation warning at runtime.

And maybe make 2to3 replacing time.clock() with time.process_time() or time.perf_counter()?