My feeling is the bigger jib is killer fast for the usual reasons with a sweet spot of about 8 true from those that are using them. So this makes it a true light jib and would allow the std class jib to be more of med-hvy...pushing its range up quite a bit...maybe to the point where the class 'heavy' jib isn't needed?
Snap: I guess the reason NOT to have them like this that it removes the furler and requires drops instead of furling. And that's a whole other contentious bit I'll leave to the class.
Helm: Agree about the helm, but on the 10 it is more about keel/rudder/hull, as more and more rake doesn't appreciably add to the helm. The boat feels right with this jib. Maybe the net increase in power at the bottom range helps the helm by loading up the boat in general?
Mainsail: Generally, mains have been getting flatter and flatter, noticeably on rigs like this that can be made quite stiff because of the rig geometry or because of carbon masts. As a result the sail designers don't have to design a lot of luff curve into the sail (so that the sail doesn't turn inside out when the mast is bent).
Stiff rig and tuning allows designers to make the main flatter to begin with (less luff curve) and this results in more roach and the bigger the roach (think fat head) the more the sail will twist easily to depower. Since the girths are fixed by the class rules this results in a sail that is 'bigger' in profile. In this case it might only be 76mm or so, depending how flat/full the one might be.
And as we all know, getting the 10 powered-up, isn’t really the issue, so the need to have a big plump main in light air is over rated.
Battens: Top two are more parallel to the foot. This reduces some of the compression on them and allows the top to twist more readily.
The bottom three are perpendicular to the straight line leech, more or less. Right angle extends the batten further into the sail, so in theory you need less batten length to do the same job as battens parallel to the foot.
This isn’t the reason though. When I design things I try to make sails clean visually and clean from the manufacturing POV. So you notice that all the battens, stripes, windows, do not cross panel or section seams. (had the battens been parallel to the foot, they would have overlapped or been on top of section seams). Doing this means that all of these components can be put on the sail before the sail is assembled. Makes it easier and faster to build and makes the finished product less mangled by machines and hands. And it looks good. Doesn’t always happen like that, but I start with this in mind.