Light Enabled didn't seem to affect me that much, either. I was around 925 when I started, and now I'm at 946 thanks to the Pinnacle drops, I never really felt over powered.
I'm not sure if it was a feature or bug, but I was able to do two of the IB bounties twice.
Oh I feel it big time.
I'm 929 and almost everyone I go against is 950+ usually 960. The advantage is pretty insane once you get 20 level differences.
I usually dominate crucible with a 3KDA+ and I can barely get a 1KDA in 95% of these matches, I feel like I'm shooting marshmellows, golden guns don't one shot, arc staff doesn't one shot, shotties don't one shot, it's cruel lol.