I appreciated the informative review (and subsequent follow-up) on these two pistols, mag318. I hope what you suspect regarding the cause of the Nano's eventual malfunctions (design defect) isn't true because that's the hardest thing to "fix". Things like poor workmanship and tired springs can be dealt with by the shooter much more readily than a design defect.
I also agree that an external slide hold-open feature (even if the slide isn't being held back after the last shot-ala Ruger LCP) is especially noteworthy in the event of a malfunction.