What was originally communicated as requirements:
Commander Ashoka Tano will be heading to a new Event called “Proving Grounds.” This Event will have a monthly cadence and will allow you to earn her shards for FREE, so long as you have the prerequisite to enter.
Requirements:
Must not already own the unit at 7*
Must not already own enough shards to 7* the unit
Once you obtain the unit at 7* or have enough shards to 7* the unit, they will no longer be accessible.
This is not meant to be a source for Shard Shop Currency, this is an opportunity to get characters that were once exclusive to Conquest.
The 4M GP requirement is kind of a slap in the face, honestly. Hard to say I'm surprised they found a way to make a great thing terrible, though...
I mean, I could almost understand if the GP requirement was 2M (the barrier for Normal Conquest). That at least would be "understandable."