Currently Enhance plans can be updated, but they are applicable only to new customers. This is a good way to do it, where you can keep old customers on older plans and then move the newer ones to new plans.
But if in general all customers need to be updated to the new plans, this should be possible too.
Also, in cPanel there are different ways to update the package per user if needed, like update the user package to say for eg. 20 emails instead of the package specific 10, for some genuine reason. Then this can be supported too, keeping the same package for that user only. So editing a plan on per user level can be achieved instead of updating all the user plans.
Most providers bill backup separately, so it would be great to have a uniform backup system at enhance.
eg.
Plan A: 2 websites, 20gb space, 200gb bandwidth, no backups, etc.
Plan A with Backup: 2 websites, 20gb space, 200gb bandwidth, backups included, etc.
We have to create two plans currently as shown above with backup and without backup, instead backup can be an option and can be selected while provisioning if the customer requires it as an option. So it would be like,
Plan A: 2 websites, 20gb space, 200gb bandwidth, etc.
Customer checks the option for backup, backup is assigned to him, he unchecks the option, backup is not assigned to him.