At Unity, we work with our users to continually improve our services and move them in the right direction to support their needs.
The original design for Cloud Save called for dividing player data into a number of lots of limited size, originally 200 slots of 16KB each. If users have a higher storage requirement than this then they would need to split their save data up into chunks which made the use of this service more complex.
After hearing your voice we are pleased to announce the development team has solved this issue. Users now have a total amount of 5MB per player to work with, and you can distribute your data across keys in any way you see fit. We have also raised the maximum number of keys to 2000 per player.