To be sure that we're on the same wave length Y (actually double Y) vs. V (bridged):
Both has it's pros & cons. Actually it depends on the targeted segment which bridle to use. Many bridles will work on the same design, it just depends what designer wants out of it.
Regarding that power statement of mine, different bridles acts differently on load distribution over the kite structure, here's one sample:
(regarding the power some bridles might not be the right choice... that's why you also see more V (bridged) bridles on LW kites recently)
PS: If we're discussing on Y/V front lines only (original thread) - I don't use Y, but if I'd do I'd make it as short as possible (depends on how you want your safety settled), since Y messes too much with pivot point of the kite plus some other things.
Y bridle (with at least some pulleys) allows the kite to better change the angles, allowing the kite to roll more easily and to relaunch a bit easier on a shorter bridle. Drawback is less power.
V (bridge) bridle has more power but it also can not change angles so much at least the one w/o pulleys, also the relaunch is a bit harder with more pull from the kite.
the Y is dead but it has nothing to do with performance. Y relies on the bridle to roll the kite on its back. This requires long bridles and usually pulleys. Cabrinha recently left Y because they were making new kites with short bridles and it had to use the V. That's basically it. If you look at liquid force, you can check out the new 2014 Envy compare it to the 2013 Envy the old envy has a long bridle pulleys and can use a Y, but back in 2010 liquid force switched from Y to V so now when they came out with this direct connection short bridled Envy they don't have to redesign the control bar.
North will also have to give up the Y too if they want to change their 4 line kite design.
So yeah there are these other things a kiter might notice the Y will press in a few pounds of force on the kite, the V might allow you to do tricky self landing techniques or uninvert the kite out on the water, the Y has it's own bag of tricks for self launch and landing, but what is really going on here is that the Y safety system imposes design constraints on the kite design, that's why it lost the control bar wars.
A Y requires a certain type of bridle on the kite and won't safely flag out some types of kites. A V flag out system works with any kite. That's why the Y system lost.