Your post doesn't really convey a consistent thought.
I think you misunderstand the waiting I mentioned; if everyone has to wait, then that by itself is not a big deal, not too different from waiting for a mini rig today.
The issue is if
you have to wait x months while other customers are already getting their asic miners and pushing up difficulty. Then you will have a problem. Particularly if that waiting list is caused by a massive backlog.
But no matter how BFL handles this, with high or low initial per GH prices, long or short waiting lists, unless you get an insight in to BFLs actual and future sales, it will be impossible to calculate a ROI time and if BFL strives for maximum return on its own investment, you will likely not achieve a positive ROI in your lifetime.