WARNING: NOOB INPUT!
From just looking at the different ways to construct the "LED blade". there is a factor to consider- rigidity.
Strength & durability of the LED string will not be from being rigid. When swinging Polyarbonate blades, anyone can tell you that the blade bends before it breaks. that's why it absorbs the force of the blow and doesn't break. its when the blade flexes that the LEDs are the most vulnerable. if it doesn't bend with the blade, that is when breaks in the ladder can occur. using quality wire instead of direct connections to the LEDs might offer a bit more flex, and thus last longer...
...though in my opinion: LEDs in the blade is a bad idea for the dedicated duelist as it is not a question of "if" an LED blade will break or burn out, but "when" will you have to replace it and how much it will cost you. stick to the LED blade if you want it just for show. that's where its true strength lies. Using uniform electronic quick disconnects can allow you to have the best of both worlds if you configure your hilt to accomodate both "ultrabrights"(light source in the hilt) & "LED blades"(light source in the blade).
Just my 2 cents. feel free to dismiss at your discresion.