Stackoverflow discourages asking questions such as "what is the best X for purpose Y?". I fear that "what is the best profiler for Flask on GAE?" matches this discouraged pattern, which might lead to downvotes etc.
I think it's critical that before we suggest a question be moved to Stackoverflow we make 100% certain that it does not risk conflicting with the site's guidelines. In this case, the guideline might be...:
"""
To prevent your question from being flagged and possibly removed, avoid asking subjective questions where …
every answer is equally valid: “What’s your favorite ______?”
"""
Alex