There are a lot of people I've spoken to who don't really approve of Neil Wagner and his mercenary approach, but personally, I'm not so fussed. As long as he makes the national side on merit, and increases the standard of play, he's as entitled to his place as the Wellington-born Ross Taylor (or the Indian-born Ish Sodhi, or Perth-born Dean Brownlie) because he is a good enough cricketer and he gives 100% every time he plays.
A more liberal approach to nationality is also helping the game to grow in Associate nations. Many expatriates are instrumental in the history of cricket in their adopted countries. They may not be household names, but André Leslie, Joe Scuderi and Ed Pearson have all been instrumental to the development of cricket worldwide, both on and off the field.
However, I wonder sometimes if the somewhat imperial rules regarding Full Member players might be a hindrance. Once a player has played for a Full Member, they have to wait for years before playing for an Associate, but if the process is reversed, the ex-Associate could be a Test player the following day. I personally have no trouble with either, but I do think that one rule should apply to everyone.
Finally, there is the fact that the more quality players you can get playing, the stronger the world of cricket will be. Dirk Nannes might re-qualify for the Netherlands; Ed Joyce has re-qualified for Ireland. Both players benefit the standard of Associate cricket. One day, it might be nice to see Ollie Rayner turn out for Germany, or Benny Howell for France, and I think it's very important that cricket embraces such opportunities for cricket to spread and standards to improve.