I think you missed the points of the criticisms being made for this event. It was not the medals being available in Reboot that was the issue, it was an issue because these medals (which are BiS and coveted by many players) are able to acquired through NX payments. As argued exhaustively by many players, the acquisition through NX was the issue. Since you have not stated that the medals can be attained elsewhere, I feel it unfair to remove the medals for Reboot players. Why does it HAVE to be attained through NX purchases? I was personally looking forward to and it's all I really cared for in this Re:Zero event. I don't see why Reboot players need to lose out on such a good medal.
Ultimately, I think the compromise should have been to remove the NX cost from the boxes. In light of promised transparency, can you provide proper justification for the current decision to remove it from the boxes and not the one advocated by other Maplers (remove NX cost)?