I think the RWC is a great thing, simply because it puts on the same field all the best nations in the World. Then, it is a great opportunity for the minnows; they have a chance to play against the great teams. If not for the RWC, Portugal would have never played against the All Blacks or Georgia would have never played against South Africa (in 2003). And because of the World Cup, rugby can have some interest in more countries.
However, I can see the point: test rugby is being devaluated.
This year we've had the All Blacks resting their best 22 players for the first 7 rounds of the Super 14, South Africa sending a weakened squad to the Antipodes in the Tri-Nations & Wales playing a third or fourth choice XV at Twickers in one of the warm-up games and going down by a record score. All done in the name of the World Cup.
I would take Wales out of this picture. Usually there are no test matches in Europe in August and September; and outside the 5/6 Nations, seldom VERY seldom do British teams, France and Italy face each other. That match at Twickers was just a warm-up game! A match where you try new tactics and test those players who are not 100% that they will be in the final squad. And where best players are often removed because you don't want that they get injured. Before the 2003 RWC, England lost to France in Paris... If it were for me, I would not give test status to those warm up matches.