I agree that a scaling BR is good but the way FC chose to make it "situational" was bad.
Overwriting all reflects on trader? You couldn't think of anything better than that? >.<
Have BR scale like you proposed.
Have BR last 10 sec on target and last 30s on trader.
Have cooldown be 1 min.
Have the positive effects like you proposed but the positive effect should not appear in our NCU if we have any reflect-buff there already.
Alternatively make the +reflect buff on the trader very small across the board so that it+rrfe wont be OP. For example +5 reflect to trader across the board and negative effect on target scales like you proposed. Or whatever.
That's just one approach though. There are other, completely different, approaches you could take as well to making this situational, useful but not OP. You got a lot of different approaches to choose from. So why choose one that just leads to frustration?
Going directly for the approach that cancels reflects on the trader is in my mind just turning an annoying nano for soldiers into a nano that is annoying for everyone AND annoying for the trader. Who exactly is supposed to end up having fun with this nano now?
Instead of spreading the "annoyance" around like butter on a piece of bread, how about making it a situational nano that has a reasonable effect when the situation calls for it, with cast-time for example as a situational drawback and then just leave it at that?
There's no need for BR to have a negative effect on the trader.