I'm firmly in the Murali camp on the issue of throwing but a few things do come to mind when it comes up on a regular basis;
1) Flexion and extension are completely different things to hyper-extension. The 15 degrees only relates to the former because they are the only ones somewhat under voluntary control and so are exempt from being included in the measurement (aside from quantifying where one begins to measure). If some freakish bowler's arm bends 30 degrees behind the join of his elbow at the point of delivery and he's able to bowl 150Km because of it, it may look like a chuck but it's not. This is why still photos were, remain and always will be totally pointless in threads like this and I take it as a marker of an agenda at play when someone posts one.
2) Call me cynical but I'm always somewhat dumbfounded when people are surprised that all bowlers throw to a degree or, worse, deny that some do. I mean, really, you're moving flexible levers with more flexible connective tissue joined together with bendy and stretchy muscles through a non-vacuum as fast as possible (most of the time). What else would you expect? It's impossible for a human not to have some degree of flex/extend in their delivery and it would be helpful if people abandoned that fiction.
3) The 15 degrees was developed with respect to when a throw becomes visible, the implicit assumption being that at that point, the advantages that come with throwing the ball, instead of bowling it, align with that measurement. But what if it doesn't? What if, in reality, spinners are able to gain enough of an 'unfair' advantage at 10 degrees of flexion to make them international standard bowlers? Is it the same for everyone or largely an individual thing? Can this advantage be be measured and, if so, should it and bowlers sanctioned? Is it 'unfair'?
4) On the device itself, although voluntary at the moment, will all players have to wear it all the time eventually? If not, and, say, you only make bowlers who are being investigated wear it, won't this have the same problems as measuring them in a lab (read: gaming) if they feel they do have something to hide? Hot day 5, two wickets to win, oppo needs 20, will a bowler hold back if they're wearing these sensors?