A Couple Little Things I'm Wondering About

Staccato effect?  Sure, for people who can hear tiny change in few nanoseconds between supports  (hundreds of MHz). 
Let's assume that somebody can hear the difference.  To me it doesn't matter if this difference is real or it is only a placebo effect.  Outcome is the same.

+1 rodman99999  Electric current is a motion of electric charge. The same amount of electric charge that leaves the source comes back to it.  Energy has to be delivered different way.  It is delivered on the outside of the cable (most of it between wires, but some outside) in form of electromagnetic wave.  Even when AC current changes direction electromagnetic wave doesn't - it is always from source to load.  Electromagnetic wave around the wires travels thru dielectric.  This dielectric affects speed of electricity, capacitance, dielectric absorption etc.  When you place cable on the floor some small fraction of electromagnetic wave travels thru floor impacting a little dielectric constant (wood has higher dielectric constant than air).  How audible it is I don't know.  In my system cables hang in the air between amp and speakers, but with other cables I don't remember hearing any difference.  It does not mean there is no difference.  Some people have better hearing and better systems than mine.

Sorry, but speed of electricity in the wire is dielectric dependent and is far from the speed of light (around 0.6 of it).  In practical terms it is approx. 5ns/m in typical insulated wire and 3.33ns/m in the vacuum.
Since dielectric affects the speed of electricity it also affects capacitance, dielectric absorption etc.   As for audibility - I don't know, but don't know enough to call it ludicrous.