The key is to combine "minimalistic living" with life hacks. Reduce your life down to the essentials, then use life hacks to go even further.

For example: you probably won't get away without paying your bills so a "life hack" that automates that process will take another load of your shoulders.'

On the other hand, a "life hack" for storing "all your stuff" might not be as good as simply "get rid of all your crap"

Also good point about life design, there's not much point in "saving x minutes" or earning "x dollars" if you don't do anything useful and worthwhile with it

All in all the most important thing is to have a process, call it kaizen, constant improvement, or whatever. Try different things, measure / see what works, learn from the mistakes, rinse - repeat