The best replacement for debugging is testing.

The best alternatives to debugging are rated as following:
★★★★★  testing
★★★  tracing
★★  logging
★  unit testing
  compiling

Your alternative for debugging is not listed? Suggest!
Speaking about debugging, one probably shouldn't forget about visual studio.

Other search terms related to debugging and their ratings are:
★★★★★ visual studio
★ windbg
vs 2012
You have in mind a companion for debugging and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of debugging in all years. Click on graph for more.
debugging
testing
tracing