From watching JRLO the main positive is that a lot more people are getting to see rugby in person. The Sunwolves stadium used to get about 8-15,000 a match if i remember right. At the same stadium 6,000 attend JRLO and that is just one team out of 24.
However, I'm a little concerned in a gulf in quality between the league and what is required for Japan internationally (i.e. to compete with Tier 1). There are actually few foreigners, so all that Japanese talent is spread very thin over 24 sides (or at least across the top 12 sides). It is unlikely a promising young Japanese prop is going to be severely tested in this league so we may get more situations like Himeno going to another league to develop their skills better. I'd actually hope for a lot more foreigners in the league in the short term to raise the overall standard that young Japanese players are exposed to. At the moment it looks a little too easy for a truly top player in the league (be they Japanese or from overseas) to dominate the opposition.
In contrast I think MLR, SLAR and the Russian and Romanian leagues offer good experience for the currently lower level the respective national sides play at. Those leagues can hopefully develop and improve their standard hand in hand with improvements to the international side, but with Japan I don't think Jamie Joseph will be thrilled by the level his players are being exposed to compared to the Sunwolves days. It makes his life harder and really makes his close results against Scotland and Australia in November all the more impressive.
www.planetrugby.com
Awesome! 
