> Is it just me or would the material strength of 3D printed items have to become exponentially better for them to become a success for any kind of serious use?

Well, right now with today's technology you can 3D print multishot guns and rifles.

http://www.theverge.com/2013/5/6/4304164/video-of-defense-di...

http://www.theverge.com/2013/5/20/4348360/lulz-liberator-gun...

http://www.theverge.com/2013/8/4/4588162/worlds-first-3d-pri...