I shoot ALOT of entertainment and bands, in low light. I have always stated that f2.8 is the minimum you need for that type of work. f4 doesn't cut it.
But I rarely use a wide angle, even close up in the pit. The 35mm L is a great lens, just not for concert stuff.
If you want to see "magic" in low light, try renting a 300mm IS f2.8.
I use 4 lenses when shooting at a medium or large venue;
50mm L f1.2 for full band / full stage shots.
70-200mm L IS f2.8 for up close in the pit
300mm and 400mm IS f2.8 from the balcony or soundboard area
Shooting from the pit, you are always "looking up" at the performers. Much better angle from farther back, but you need reach.
shooting HD 1080p with a Canon 5D mkII using a 400mm f2.8 is amazing. Be sure to turn off IS when using tripod. I shoot 1/30 sec @ f8, ISO 1600 -- and even in dark lighting on stage, everything is bright with deep DOF at f8.
[Image links removed by OP]