I'd like to add the reason why bendy battens, though they may work moderately well on a light daysailer, used on flat water in a limited range of wind speeds, are not so good when you take them offshore. As the boat pitches and rolls over the seas, the whole rig "pants", cycling between too much camber and too little camber. This not only does nothing for the performance, it also wears the rig out faster, through extra fatigue and chafe. So however the camber is added, it ought to be added in a stable form - one that results in the sail blowing out easily into the designed shape (whatever you think that ought to be), but no more (and no less). As Arne said, bendy battens give too little camber in light winds, too much in strong winds: it's the opposite of what we would like to see.
A slim, light, easily driven boat can get away with less camber than a wide, deep, heavy boat, but they both benefit from having some. The difference is that it is desirable in the former, verging on essential in the latter. Ernie, your good-looking Tariand your proposed big cat will both fall into the former category, and flattish sails with little camber will be fine; but it's a different story for a heavy offshore monohull, where the right amount of camber, in the right position, becomes more of an issue.
It is quite often seen that where a boat has a "good tack" and a "bad tack", the "good tack" is when the mast is behind the sail. If the sail is flat, there is a separation bubble behind the luff, and the airflow should re-attach further downstream; if there is some camber in each panel, the mast gets buried in the sail, and the airflow doesn't see it; if the batten has a slight horizontal 'S' bend, again, the air flow tends to leap over the mast without seeing it, to re-attach on the curve of the cloth further back. If the mast is on the windward side, in all cases the sail works better, with a clean curve on the lee side - but there is a lot of parasitic drag from the exposed mast, which more than negates that extra performance.