Former WWE and WCW star Lance Storm took to his blog on his website and authored a piece about TNA switching back to the six sided ring.  Storm makes several compelling arguments for why this decision wasn't good from a talent standpoint.  Here are a couple excerpts:

The first and obvious fact is that the six sided ring is stiffer.  Now granted I've never worked in a six sided ring, but I've spoken to many who have and they say unanimously that when they switched from the hexagon to the square ring, the ring was significantly softer.  Creating a six sided ring is more mechanically challenging and constructing a floor that gives well is much easily accomplished with only four sides.  A stiffer ring means one of two things are going to happen, the boys will either have to tone down their style taking fewer or less dramatic bumps, or they are going to have to put up with increased damage to their bodies which will eventually lead to more injuries and potentially increased dependency on pain killers.  Neither of these options are a good thing and this alone illustrates how this particular decision should not be made by people in the company who don't have to work in it.

Storm also commented on one of the production drawbacks, in his opinion, of shooting action that is occurring inside a six-sided ring.

Another factor that no one seems to be aware of is that the six sided ring doesn't shoot as well for television, and TNA iMPACT Wrestling is becoming more of a television wrestling company.  Why doesn't it shoot well for TV, you ask?  Well, it's quite obvious if you sit down and think about it a little.  When you set the ring up for TV you need to have a clear view from the hard camera (the stationary camera used for most if not all distance shots).  To get the best view, you have to put a flat side of the ring facing the hard camera.  In a square ring you then have flat sides along the right and left of your TV screen.  This allows the majority of your running spots, etc. to run side to side on your screen, which is the best angle to shoot most spots.

You can check out Lance's full blog at this link.