I'd call Mills an ODI spearhead.
He has been among the best ODI bowlers in the world now, not a pace spearhead, but a Bracken like bowler.
Remember Bond has only played 19 tests (I think) over the last decade, so although it would be great to have him in our test attack it's not really weakened as he hardly played.
In a couple of years Southee could develop, but we have to give him time and not just say he should be great at the age of 21.
I think Bond should of just kept on playing until he got injured again, then retired, or he should make a test comeback for one match against Aussie or something., just so we can try and brake our 19 year winless run against them.