I would love if they made proper decent quality Christmas lights. I would pay $50-$100 per 25' strand if I knew they were good quality and were UV resistent and had life time replaceable parts (Ex: not a fly by night thing where they stop making them after a few years). The Noma "Santa Lights" C9s from Canadian Tire were great for that, because they were so standard and they made them for so long. But with LEDs most of them are built in bulbs and use crap quality LED modules and not one set is the same from the other and they have different ones each year. Also they don't rectify/filter them so lot of them flicker at 60hz. It's hit and miss and you don't know until you plug them in. Some times they have displays in the store but it's harder to tell in the store because with them all lit next to each other the flicker is everywhere. I wonder if some people get seizures in that aisle lol.
If they used proper high lumen LED modules and higher quality plastics, and designed them so that they are sized for 170VDC and would be fully rectified and filtered they would be way better and brighter. But everything is built down to a price now days, pisses me off.
What I'd like to see is fully addressable RGB ones that provide signal wires that would use a simple open source protocol. Make the bulbs changeable too in case they go bad. Yeah that's never gonna happen... but wishful thinking. The closest thing is to get RGB strips. I'd like to play with those some day.
One of these days I need to look into what it would take to make my own. I would design them so they can be permanently installed on the house. Maybe doable with 3D printing and the right type of filament.