A nice idea, but the arrow idea may be harder to implement with some types of sliders. There are some tightly zig-zagging slider, and there are sliders that intersect. It would be hard to implement the design with these kinds of sliders around.
Nonetheless, the transparency of the slider is a great idea, I like it.
Made a skin which doesn't use any borders (circle or slider, cheated slider by using black border with 100% bg dim). Looks pretty awesome imo, white borders kept annoying me like hell. Play with that skin: https://www.youtube.com/watch?v=maZTJNoCJfc Can we have something like this?
also don't mind the play, it's older than my name change; just picked one randomly
This hasn't been said in this thread, but it seems important: The way sliders work now is that a hit circle is displayed on each endpoint on top of the slider track. For transparent sliders this means that it's impossible to have the same color for both the slider body and the endpoints. It would be great if there was a way around this problem. For example, have separate hit circles for sliders.
Secondly, I'd love to see transparency for slidertype 1. I like slidertype 1 and while it seems to have fallen out of favor, it still fits well with certain skin styles.