Lying is wrong[1]. Therefore, it is bad to base your banking system on it. It's the typical thing where the costs to the system accrete over time and then cause a crisis: the elites are bailed out, the taxpayers eat it.
There wouldn't need to be a reserve ratio. A dollar could, in theory, be lent out an infinite number of times, so long as that dollar were lent (and saved) at increasingly shorter durations. At any given point of time, a single person "owns" that dollar. Of course, the market would signal what dollars were available when. And, also, loan losses would need to be covered out of other profits by banks (who would need to charge service fees for, well, the services they provide, rather than hiding behind long/short duration arbitrage)
(I'm also in favor of a citizens dividend for controlling money growth, and a modern debt jubilee per Steve Keen. So, yes, you can safely ignore anything I say as implausible, almost certainly wrong, and unlikely to ever be realistically considered by the powers that be. This has one advantage, however: I will never be proven wrong :)
[1] - see all moral traditions across all cultures, or ask mom