Everyone has there own opinion, here are a few ideas of mine.
1 Four line bars that have four lines of the same length, not a single front line that Y's near the kite.
2 Coated centre line through bar.
3 Depower within reach and above the bar.
3 Short depower travel bars.
4 Safety line attachment point at base of Quick Release.
5 Soft Bar ends/winders
6 Good grip around bar that lasts/wont peel away.
There are many good kite bars on the market, some not so good.
I would like to put one together with the parts I like from various brands.
Krispy, I would like to see what you come up with.

Keep it simple :)