I don't believe the issue is with Irish Provinces per se poaching NZ talent, its that they are doing so with the financial assistance of the IRFU; that is the bone of contention. Apart from John Afoa, it looks suspiciousy like the IRFU buying players to become future Irish Internationals. As soon as Jared Payne was mentioned, some Irish media already had him the the Ireland squad, and he's still playing here in NZ!!
However, I think FlukeArtist is right. As long ago as 2000 the doomsayers were predicting that the European Clubs would gut NZ of talent and that we would begin a steady slide down the rankings as all the talent ends up in Europe. The British Media made jokes about the last player leaving NZ to turn off the lights. Well the joke is on them, because it hasn't happened, and shows no sign of doing so. New Zealand could field a "second 22" side that could beat any International team in Europe except England and France, who they would likely be the equal of.
However, it is about time that the NZRU took steps to protect their investment. They must be heartily sick of paying to develop these players only to be out-priced by EuroCash.
I would like to see them adopt a similar system, that the military do here, a "return of service" for the money invested. When the military send a member on a course of training, the member must sign a contract guaranteeing they they will not apply for a discharge for a period of time after they return. For example, when I was posted to Moffat Naval Air Station in California in 1985 for a maintenance course on the (then) new Orion Doppler Radar, I had to contract for three years on my return, so that the Air Force got a return on their investment. If I wanted out before that time, I would have to buy out of my contract.
Similarly, I think NZ rugby players should be signing a minimum four year contract before they are even allowed to set foot on the field in an ITM Cup. At this point, they begin to accrue a "dollar value" commensurate with the amount of money the NZRU spend on their development. If they get selected for Super Rugby, they sign another minimum four year contract (which encompasses the ITM Cup contract) and their dollar value goes up accordingly. Get selected for the All Blacks, another four year contract (encompassing the previous two) and a further increase in their value.
If at any time, a player decides they want to play in Europe or another country, they must buy out of their contract, or have their new club buy them out. For example, a player like Jared Payne might have an accumulated value to the NZRU of $350K plus whatever time he had to run on his contract, say another three years at $100K p.a.
Ulster might balk at having to pay a transfer fee to the NZRU of $650K on top of whatever they offer him, but if they decide he is worth it, the NZRU at least gets $650K to help pay for the next cab off the rank.