> One thing to keep in mind is that python 3 is still considerably slower than python 2.
You have wrong information.
You have wrong information.
It would be very hard for someone to say "python 3 is considerably slower". Startup is significantly slower, yes, but that's about it.
A tool gathering imports in one file if it is safe to do so would be really quite neat for deploying interactive Python applications (command line / GUIs).
On the more extreme end you'd have a C application linking not too many libraries (symbols are lazily loaded, libraries are not) that reaches main after 0.0001-0.0002 s (i.e. one to two hundred µs).
On the other extreme would be Java apps using heavy runtime-code-generating frameworks like Spring, where even a trivial app can take up to ten seconds to spring to life.