I think the June shipping is some form of smoke-screen for the S5 against the next-gen (S6?), thus banish the thought any potential customer may have to hold back until the next-gen is out!
 
With their track record, bitmain have never done pre-orders, and though their reputation in the industry precedes them, they are well aware of the community's attitude towards pre-orders, and wouldn't tarnish their reputation by doing one on existing hardware. I have to say I hope they have replaced the fan or tweaked /added settings for controlling the fan.