Yeah, plenty of opportunities recently, and quite rightly dropped during our last series. My point is if you're looking for a reason (and it doesn't have to be the sole reason) why he hasn't kicked on like many have expected him too look at how he was treated during his first two and abit years of test cricket. He was never given a consistant run in the test squad, I mean I think it took almost two years before he was given a chance to play three tests in a row, which is staggering really, a good way to mess with someones head.
To be honest, if being dropped a couple of times early in your career is enough to permanently stunt your development, then I think Southee's got bigger problems than his bowling action. Not to say that Southee wasn't unlucky with his selection. He definitely should've gotten a longer run in the team after the 2008 Aus tour (but the selection around bowlers was generally weird during that time, Chris Martin got dropped after the same tour for similarly opaque reasons). But good, mentally tough cricketers would use that as motivation to really work on their game, come back and establish their place (such as Dale Steyn did after being selected and dropped in 2005).
In my opinion, Southee's problems are twofold:
a) He was selected when he was too young. The case for his selection was fairly weak, he had a good, but not outstanding FC record (averaging around 28 iirc) and had played only a handful of matches. The selection seemed to be more based around public excitement at his u19 success than his domestic form demanding a place in the side. As a result he was thrust into the spotlight, which involved all sorts of public comment on his action, variations, and in particular, his pace (just weeks after his first success, that moron Mark Richardson was already moaning about how Southee wasn't a genuine quick). As a result he's spent the last few years tinkering and adjusting his bowling style and strategies under intense scrutiny, rather than naturally developing in a more forgiving environment.
b) He simply hasn't had the opportunity to play any FC cricket. Rightly, or wrongly, he's become a fixture in the ODI side, which gives him little chance to play for ND in the plunket shield. When he does play, its usually one or two games at the start of the season, when conditions are stacked in his favour. Being an ODI player has also encouraged him to focus on aspects of his bowling that are irrelavent to test cricket (e.g. bowling yorkers and slower balls), and focus less on swing bowling. That's why other bowlers, like Boult and Bracewell (lesser cricketers at u19 level), are now bowling better than he is in test cricket. They've actually had a decent opportunity in the last couple of years to play some FC cricket, and learn what does and doesn't work for them in the longer version of the game.
That's why, imo Southee needs some FC cricket (preferably of a slightly higher standard than the plunket shield, but anything will do at this point).