Yep, I not saying I agree with Turunui, just his opinion. I agree it's a problem, RA (or NZR) don't have endless supplies of cash to always keep all players, hell even RFU in England lose players to France and they like NZ don't then pick them. I agree with what you say RA has seemd to adjusted with the sabbatical deals etc, and I feel this a good compromise.
I don't think changing the reg 8 dates is the complete answer and have no idea what is, except for unions to only play in the test window so their players are supposedly available. Though I suspect some of the availability issue at times is players just wanting a rest? So can get a convenient twinge etc (I peeking at Skelton who is one that doesn't seem to be breaking his neck to play in every test he can). I could be wrong , but just have had impression (and could be miles off) that he perhaps picks which tests he wants to play in.