I think the difference is that few (any?) RV-8s come equipped with autopilots, glass cockpits and ballistic parachutes as standard, whereas the Cirrus does.
That is not the point.
The point is there are many high performance aircraft (in terms of speed, not avionics) and some of these aircraft can only be legally flown in VMC.
Which demonstrates that in both practical and legal terms we have no problem as a community flying high performance aircraft in VMC any more or less than we accept lower performance aircraft may be flown in VMC.
From my experience flying a Cirrus and many other aircraft there is no reason at all why the aircraft cannot be safely operated by a pilot restricted to VMC any more than any other aircraft of similar or lesser performance. I would go further and say there is nothing about a Cirrus which makes it more likely to find yourself in IMC than for any other aircraft type subject as always to the pilot have received adequate training on type.
Quite simply I believe it is just wrong to suggest its the aircraft fault when an involuntary incursion into IMC occurs, there is no more or less reason why a VFR pilot cant operate a Cirrus, than an RV8 than a Warrior.
Having flown with many pilots who are new to higher performance aircraft the "problem" they always have to conquer is the additional speed with which the scenery passes. The often reported nonsense that the Cirrus is difficult to hand fly and that the pilot requires and intimate knowledge of the avionics and autopilot is just that. It is a delight to hand fly for hours on end, and once you are accustom to a glass display the information is more intuitively presented and the pilot requires to interact very little with the avionics.